Home improvement projects can easily cost tens of thousands of dollars, which means the stakes are high if something goes wrong.

And things do. Maryland regulators received more than 4,400 complaints about home improvement contractors in the last three fiscal years, ranging from disputes about the scope of the project to no work performed at all.

The Maryland Home Improvement Commission, which offers a program where homeowners can be reimbursed some expenses if they have a dispute with a licensed contractor, urges thoroughly researching contractors beforehand to cut down on headaches afterward.

"Don't rely on the first person that comes up and says, 'I have the best deal for you, and it's good for today only,' " said John T. Papavasiliou, who oversees the commission as an assistant commissioner with the Department of Labor, Licensing and Regulation. "There's plenty of competition out there."

His top advice: Make sure the contractor has a Maryland home improvement license. Licensees pay into a state guaranty fund that customers with unresolved problems can file claims against. Homeowners who sign with an unlicensed contractor have no such option if the work is bad or the contractor takes the deposit and runs.

"There are people that just steal money," Papavasiliou said.

Sharon Humphrey, a retired executive assistant, said she didn't realize the contractor she hired to repair a damaged retaining wall on her Charles County property in the summer of 2012 wasn't licensed. It was a friend-of-a-friend situation — one she regrets getting involved in.

He kept delaying the start of work, she said. When he finally did get going, he didn't come close to finishing. And she was in a hurry to get it fixed.

"I was selling my house, and I knew that wall probably wouldn't pass inspection," said Humphrey, who has since moved to South Carolina.

Finally, she went to the Home Improvement Commission to try to get her money back —$2,400. And she did, after the commission coordinated on a criminal case against the contractor last year.

She knows she's lucky. Some homeowners don't get back what they lost, and the losses in some cases are much larger.

"I was surprised that I got every penny," Humphrey said.

She had a much better experience with the licensed contractor she hired to repair the repair: He got it done quickly and for less money.

Still, picking a licensed contractor is no guarantee of a problem-free experience. More than half the complaints to the commission last fiscal year were about licensees.

And when customers file a claim, they often get substantially less from the guaranty fund than they were hoping for. The average claim in the last three fiscal years: just over $14,000. The average award: just under $8,000. (The limit per claim is $20,000.)

Paul Dowell, a pharmacist who lives in Howard County, is frustrated by both the size of his guaranty-fund award and the years it took to get the initial decision involving his $117,000 home-improvement project in 2009. It's a case the state described as unusual for both its length and complexity.

The project was primarily an addition. But the work also included a new roof, repairs to termite-damaged floor joists and property regrading, and all three were at issue when Dowell had a hearing on his guaranty-fund claim last summer.

An administrative law judge said in his ruling that the roof, which leaked, was "inadequate and unworkmanlike" because it didn't match the pitch the architectural designs called for and the ridge vents required. Judge Stephen J. Nichols also used "inadequate" to describe the slope of the grading as well as the floor-joist replacement, because the contractor didn't use pressure-treated lumber as required.

The judge awarded Dowell about $7,800. Dowell, though, had asked for substantially more. He paid $13,000 for repairs to the roof and floor and had estimates averaging $6,400 to regrade his property.

"People don't realize if you file a claim against the guaranty fund, you not only have to face the contractor, but the attorney general's office sends an assistant attorney general in there to defend the guaranty fund," he said. "You've got to sit there and fight those two people."