After four years of waiting to address a full chamber of senators on a major issue, Sen. Daniel J. Evans (R-Wash.) finally got his chance. It was 1 o'clock on a Sunday morning, he had been allotted two minutes to sum up his views on aid to the Nicaraguan contras, and hardly anyone was awake enough to listen.

For Sen. Paul S. Trible Jr. (R-Va.), the problem was closer to home. His daughter, Mary Katherine, had been born 10 days before he became a member of the House in 1977. If he ran for and won a second term in the Senate, she would be 18 before it was over. "She would have walked through my life and I would not have been there to see it," Trible said.

Sen. Lawton Chiles (D-Fla.), with 18 years in the Senate and seemingly inexhaustible patience and perseverance, put it more simply: "I just wasn't looking forward to another six years in the Senate. Maybe at some stage there is a little burnout."

Evans, Trible and Chiles, with a little luck, could have finished out their lives in the Senate, the envy of most other politicians across the country.

But they have decided to call it quits for a variety of reasons that have as a common denominator a profound frustration with the Senate itself -- with a life that demands all of one's time and energy without a compensating sense of achievement.

"There's a feeling of lack of accomplishment, or maybe more accurately a sense that the whole system is breaking down," said Evans.

"We offer amendments, we send out press releases, and we poll our constituents to assess their approval or disapproval," said Trible. "In the process, the Senate has become difficult to lead, consensus is illusory and the whole policy-making process stands on the brink of incoherence."

The frustration begins with the money chase, mean-spirited negativism and general vacuousness of campaigns as they are currently waged, many senators complain. But with victory comes a new set of frustrations: budget battles, filibusters, procedural stalemates and protracted struggles that "cut ever finer and finer compromises . . . never resolving anything," according to Sen. John C. Danforth (R-Mo.).

Hours, if not days or sometimes even weeks, are spent haggling over issues for which the outcome is a foregone conclusion, often a temporary fix that will require further consideration at another time.

Sen. David H. Pryor (D-Ark.) examined how the Senate filled its time last year and figured it wasted 15 to 25 percent of its working hours as it "circled in procedural holding patterns." Last year, through early December, it had spent 111 hours in quorum calls, 116 hours in recess and 56 hours in extensions of the normal 15 minutes allotted for roll-call votes, according to Pryor. "We have frittered away over a week's worth of work -- 56 hours -- waiting for votes to end," he said.

The Senate has had more filibusters in the last 19 years than it had in the preceding 127 years, he said. The Senate is also meeting longer and voting less, he said. Moreover, Pryor concluded, "There's almost nothing we do these days that is understandable to the people."

For senators with families, especially young ones, the Senate's long and erratic hours can be the most difficult problem. "It's easier on those whose marriages have already broken up," a recently divorced senator acknowledged dourly.

Some senators try to make changes but have often been thwarted by tradition, inertia and the fact that "we are 100 independent political entrepreneurs pursuing 100 independent political agendas," as Trible put it. Rules designed to protect minority viewpoints and curb the passions of the moment are used to obstruct, delay and harass, critics complain. "We are all-powerful or all-powerless, I'm not sure which," said Evans.

The Senate, Pryor said, has become a "slow-motion system of inefficiency and procedural imprisonment." "We're getting to be just a bunch of super-accountants," complained Sen. Warren B. Rudman (R-N.H.).

Even Majority Leader Robert C. Byrd (D-W.Va.), who yields to no one in his love of the place, acknowledges it has lost a lot of its appeal for reasons from the "demeaning money chase" of campaigns to the "god-awful budget process" that takes up so much of a senator's time.

"I've been here so long and I'm so wedded to the institution, it's different for me," said Byrd, 70, who has served in the Senate for nearly 30 years. "But for a younger person, who can do other things, the Senate does not have the attraction it once had." If he were 20 years younger and facing reelection to a second or third term, "I wouldn't do it either," Byrd acknowledged sadly in a recent interview.

The Senate's dropout rate has fluctuated markedly over the past decade, from a high of 10 voluntary retirements in 1978 to a low of three in 1982. But in all those earlier years, a vast majority of those who left did so because of age or illness.

Even among the six who retired in 1986, only two were under age 64, and one of them was Gary Hart (D-Colo.), who quit to pursue the presidency. Among the six who are bowing out this year, only three -- John C. Stennis (D-Miss.), Robert T. Stafford (R-Vt.) and William Proxmire (D-Wis.) -- cited age as a factor. Of the rest, Evans is the oldest at 62. Chiles is 58; Trible, 41.

Trible's seat is an example of the changing nature of the Senate and its members. It had been held for nearly a half-century by the Harry Flood Byrds, senior and junior. Trible was elected when the younger Byrd retired in 1982 and is leaving after one term, possibly to run for governor.

He will probably be succeeded by former Virginia governor Charles S. Robb, a Democrat who could well have defeated Trible if he had run again, polls showed. But Robb's stay in the Senate could be short if, as many expect, he runs at some point for higher office. What was once tantamount to a hereditary peerage has become a virtual revolving door.

What worries many senators is that the departure of Evans, Trible and Chiles may herald the beginning of a rush of retirements by first- and second-term lawmakers who are young enough to find "life after the Senate," as former majority leader Howard H. Baker Jr. (R-Tenn.) put it in quitting in 1984.

It was Chiles' surprise retirement announcement Dec. 7 that brought a lot of the private seething to the surface. By the end of his third term, the hard-working, serious-minded Chiles had risen to the chairmanship of the Budget Committee, one of the Senate's most important. But by then the post had become a relentless treadmill, providing little sense of achievement.

At a Senate Republican luncheon the day after Chiles' announcement, Evans said the five senators sitting closest to him said they doubted seriously that they would run again.

Rudman said he knows of at least a dozen senators, "some very, very good people," who are talking seriously of leaving the Senate when their terms expire in 1990 or 1992. "They say, 'I've talked to the wife and kids, I'm 58 or 60 or 62, I've got a great life ahead of me and I don't want to spend it here.' "

Rudman, who was leaning against running again in 1986 until passage of the Gramm-Rudman-Hollings budget law gave him a sense of accomplishment that he previously felt was lacking in his Senate service, counts himself among the possible dropouts for 1992. "If I'm going to make a move, I'd have to do it then," said Rudman, who will be 60 in 1992. "If I run again, I would stay here the rest of my working life."

More worrisome to some senators is that the very people who make the Senate function as well as it does are among the most frustrated: workhorses like Chiles, consensus-builders like Evans.

"When the Senate loses a Dan Evans, you know something's wrong," said Stafford.

With the loss of people like Chiles and Evans, "I'm afraid we're going to end up with a very, very partisan place," said Rudman.

Evans and Trible fall in the two high-risk groups for frustration in the Senate: former governors (Evans) and former members of the House (Trible).

As a governor, "you're used to having the initiative in your own hands; you don't in the Senate," said Evans.

House members were used to more orderly, disciplined operations as well as time to develop expertise on particular issues. As a House member, Trible said, "I always used to wonder why I seemed to know more about an issue in {House-Senate} conference than the senator sitting across from me . . . . Now I know."

"We spent millions of dollars to get here, we arrived eager and ready to work and we became embroiled immediately in impotence," said Sen. Thomas A. Daschle (D-S.D.), a former House member elected to the Senate in 1986.

But while governors and House members are most likely to become frustrated by the Senate, it has the kind of big-stage, bright-lights lure that keeps attracting them. At least four governors are running or leaning toward running for the Senate this year, along with a dozen or more House members, including some who have been outspoken in their criticism of senators and how they operate.

The fact that they do keep coming holds out hope for some senators that the critical mass needed for change is being built -- in the normally slow Senate manner. "The more new members, the more willingness to change," said Daschle.

With strong backing from the Class of 1986 freshmen, an ad hoc group headed by Pryor and Danforth has suggested several rules changes, including moves to expedite consideration of legislation, a strict 15-minute limit for roll-call votes and a more orderly process for handling amendments.

Also, Byrd arranged the calendar for this year so the Senate will get one week off every month in exchange for working a full five-day week the rest of the time. The idea was to bring some order and predictability to the Senate's operations.

If, as expected, Byrd steps down as majority leader at the end of the year, Democratic freshmen have discussed using their clout in the leadership elections as leverage to force other improvements in Senate operations.

Although he's giving up his seat, Evans has not given up on the Senate. "With a new administration, with a new Congress with new leadership, there is an opportunity for change," he said. "Pendulums do swing."