It’s down to two. You’ve vetted a long list of contractors. Wheat has emerged from chaff. Now the final decision gets tough. Each contractor appeals to you for different reasons. They’re almost identically qualified, with one difference: one’s licensed, the other isn’t.

Questions float through your head: What does it really mean to be licensed? Why are some contractors licensed and others not? And the ultimate question: Does it matter?

You’re not alone in your confusion. Contractors feel it, too. Licensing rules vary state to state. Most states require a license for at least a few home-improvement trades, some don’t. Some cities and counties require additional licenses, some don’t. Some states and municipalities strictly enforce their licensing laws, most don’t.

Once contractors think they’ve got the rules figured out for where they work, another unhappy epiphany dawns: not everyone — homeowners or contractors — knows the rules. And not everyone plays by the rules. Contractors pay a tidy sum to play by the rules in some states, which makes it hard for them to compete against those who don’t. Homeowners can pay the price when they fail to distinguish between the two.

What follows are several stories about homeowners and contractors across the country negotiating the complicated world of trade licensing. In each you’ll see the complexities and frustrations encountered in a system that can be called many things, but definitely cannot be called simple.