Norfolk could be set for a spike in cold callers knocking on doors trying to sell products and services, watchdogs have warned.
And trading standards officers have urged people to be on their guard against pushy callers, trying to pressure them to part with money for work or items.
Officers urge people to think carefully about agreeing to work on the doorstep, with some householders in Norfolk left thousands of pounds out of pocket.
Stephen Maunder, from Norfolk County Council's trading standards department, said: "We often see an increase in reports as we get into the summer months.
"Already this year, we have issued warnings about people offering roofing work, to cut trees or hedges and to pressure wash driveways.
"Our advice is that, if you want to get something done, get a recommendation from family or friends or from Norfolk County Council's Trusted Trader service. Get two or three quotes and then made a decision.
"What we are getting is people knocking on doors saying they are doing work in the area and, for example, they'd noticed a couple of missing roof tiles.
"They say they've got their ladder so will just go up and fix them for £20 or £30 in cash.
"But then, they say they've noticed something else while they are up there, such as a chimney which is about to collapse or a problem with the roof which needs to be sorted - and they've said it will cost £5,000 to £10,000."
He said some people then found it difficult to back out, so paid for work which might not have been needed, was poorly done, or for which they were overcharged.
He said: "In some cases, people have lost tens of thousands of pounds, which they've handed over to people."
He said people should not feel compelled to answer the door to cold callers, should not be afraid to tell them they are not interested and should tell them they will report them.
He said: "We don't want people living in fear, but we need to make sure that we are getting the message out there."
Norfolk Trading Standards are one of the partners in the Norfolk Against Scams Partnership, trying to make Norfolk a scam free county.
Suspicious cold callers can be reported on 0808 223 1133.
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