It's not that Nancy Thomas was ignoring her bill collections; cash flow had always been one of her company's top priorities.

But this year, the president of Walton Thomas Placements Inc., a Washington-based temporaries agency, and her staff have had to devote more time keeping their accounts receivables from getting too old.

Thomas said that since she started her company 10 years ago she has always depended on getting paid for services within 10 days of providing them. But this year, clients started taking longer to pay. The average turnaround now is 30 to 45 days.

Clients who don't pay within 10 days usually receive a form letter. After that, there are follow-up calls and the bill, if still unpaid, is eventually passed to the company's lawyer. After 90 days, Thomas refuses service before she gets paid.

Thomas makes no bones about the 10-day payment policy, even though many companies are used to having more time. She explains the policy to all new clients, and she finds those who complain that it is unusual may need more nudging than others.

"This is the first year we've had to do this," she said.

Many companies are facing firsts this year in getting paid on time.

Sue Stolov's company, Washington Independent Productions Inc., does video productions that can cost as much as $15,000. The long process that clients go through before deciding to spend that much money ensures the bill will be paid, and in a regular pattern.

But clients are less likely this year. In the past, Stolov would go ahead and start on a project, even if a customer was still seeking corporate approval of it. Now, she doesn't spend a penny before she sees the down payment.

With lenders watching companies more carefully, businesses are keeping closer tabs on their receivables both because there's less cash coming in and because banks are less likely to advance credit.

And as many business owners feel the crunch, they are doubly troubled because they do not want to give the impression to potential and first-time clients that they are in desperate need of every penny.

DJM Inc., which sells corporate gifts, opted not to offer credit at all to customers to keep prices down in its competitive field.

"Because we don't get into the bookkeeping situation, we can keep ourselves flexible," said a company spokesman, who requested anonymity. "We're more agile. If you can keep your business operating as much on a cash basis as possible, it enables you to move quickly and react quickly."

But demanding payment on delivery has led DJM into a couple of sticky situations with companies that cannot process checks on such short order.

Nancy Low, president of a Chevy Chase public relations and marketing firm that bears her name, said she has noticed a "tensing up" of client relationships over the issue of when bills are paid. With their own sales flagging, clients want results sooner but are taking longer to pay.

Low said she offers discounts for early payment, which she said has saved the company more money than charging fees for late payments. And she involves her project managers in collecting bills to keep the process as personable as possible.

Mel Chaskin, president of Vanguard Research Inc., a Fairfax-based computer services and software development firm, said he encourages prompt payment by enclosing a prepaid overnight mail envelope with every bill. For about $14 per bill, the company saves thousands of dollars in interest, Chaskin said, if a bill comes back in three days rather than three weeks.

"It's a delicate situation because you don't want to put too much pressure on your clients," said Elizabeth Esch, president of Silver Spring-based Capital Presentations Inc., which sells computer-designed graphics.

She said she finds herself running more thorough credit checks on potential clients and accepts a partial payment when a client is having difficulty paying on time.

"Everyone is finding that money is tighter, cash flow is thinner than it used to be," Esch said. "Whether they want to or not, everybody has to prioritize their payments. And often times service companies, {which} are only used occasionally, are not at the top of that list."

Standing firm on prompt payment is not an image problem for everybody. Low said she views the issue as a question of good business during tough times.

"The longer we're in business, the more our success is demonstrable, the more comfortable we are with holding the line that way," she said.