Deputy chief of staff Michael K. Deaver, whom many consider President Reagan's most important aide, is telling friends and associates that he will be leaving the White House in 1983.

Deaver, the aide closest to Nancy Reagan and the best interpreter of the president's moods, has been at Reagan's side since the early days of his California governorship in 1967.

But his personal savings have been depleted from more than $30,000 to $3,000, according to reliable accounts, and some think he no longer wants his existence defined by the Reagans.

Despite Deaver's frequent declaration of intentions, many who know him are skeptical that he will make the break.

They believe his longterm loyalty to the Reagans will govern his judgment if he is asked to stay, as he almost certainly will be.

And they doubt that anyone is likely to replace Deaver in his understanding of a president who seems more and more to want longtime California aides around him.

One who knows Deaver well says of him: "When he talks about it, he always talks about leaving.

"But I don't think the Reagans will let him go."

One Reagan administration official not talking about leaving is Office of Management and Budget Director David A. Stockman, who was so incensed last week at persistent White House reports of his departure that he lectured his staff about it at his daily meeting.

Concerned that reports he is a lame duck will make his job harder, Stockman told his aides that any of them who had given others an impression that he is leaving has an obligation to set things straight.

"I have no plans to leave in February or any other time," said Stockman, who plans to be married that month.

Scratch California from the president's itinerary for the final week of the campaign. The White House and campaign strategists for Senate candidate Pete Wilson agree that Reagan won't be much help to the Republican nominee in his battle to hold off Democratic Gov. Edmund G. (Jerry) Brown Jr.

The White House implicitly recognizes that Reagan is a polarizing influence who might induce Democrats protesting against Reaganomics to vote along party lines. Republican polls show that a significant number of Democrats are polarized in California by Brown and that they may well vote against him unless Reagan injects a higher visibility into the race.

Earlier statements by White House aides that the president planned a last-minute trip to California were fueled by information from these same polls showing that Wilson was losing nearly one-fifth of GOP voters.

Reagan's endorsement is solid gold with this electorate, particularly in California. But with new trackings showing that GOP voters finally are rallying around Wilson, the Reagan return to California was judged more a liability than an asset by Republican strategists.

The question of how much the president helps, or hurts, candidates of his party continues to be a key one as the elections approach. Reagan clearly helped GOP Senate candidate Chic Hecht in Nevada and tentatively plans another visit to that state. He'll also go to Montana for challenger Larry Williams and to New Mexico for embattled incumbent Harrison H. Schmitt.

The word from the White House is that no decision will be made on a Republican National Committee chairman replacing Richard Richards until after the election, when various defeated GOP candidates could become candidates for the job.

But talk about bringing in a Reagan intimate, Nevada Sen. Paul Laxalt, is serious. Under party rules Laxalt couldn't serve as chairman while a senator. He could, however, be named "honorary chairman" with a full-time politician doing most of the technical work.

The proposal has been discussed with Laxalt by Deaver, White House chief of staff James A. Baker III and intergovernmental relations assistant Rich Williamson, whom some see as the committee's possible "nuts-and-bolts man." "Laxalt hasn't shut the door," one White House official said Friday.

Conservative emotions about the cast of characters in the Reagan White House were truly expressed at the tribute to Labor Secretary Raymond J. Donovan last week when toastmaster M. Stanton Evans jokingly welcomed the 1,000 true believers to "the first Richard Darman memorial dinner."

In the eyes of the faithful, presidential assistant Darman has replaced Baker as public enemy No. 1 within the administration.

On the other hand, White House counselor Edwin Meese III, though not considered an ideologue within the inner councils of the White House, is clearly the conservatives' favorite White House aide. They consider him accessible and responsive to their concerns.

When Meese was introduced, he was greeted with two minutes of applause that became a standing and affectionate ovation.

Great communications from the ever-optimistic Great Communicator: praising the saving deposits bill he was signing last week in the White House Rose Garden, the president said it meant housing, jobs and growth in the economy and added: "All in all, I think we hit the jackpot."