In our part of the country, tradesmen still think of you fondly if there's a glass of lemonade or a pot of coffee set out for them. If you offer it they turn it down, but if you set it out and leave it (of course with a word or a note that it's theirs), it usually disappears. (Slice of cake not taken amiss, either.)
This doesn't affect the bottom line, but it does affect how quickly they arrive next time and how persistently they will keep trying to fix something mysterious instead of selling you a new one.
I learned this the night an electrician friend of the landlord came on the hop late one night to re-attach the most essential lines of house wiring that had been burned up in our fire, so the pipes wouldn't freeze. It was December-- COLD in that basement. When I ran the Red Cross I'd learned that volunteer firement appreciate these kindnesses from the auxiliaries. So I made a big pot of hot coffee and took it down to the landlord, my hubby, and the electrician who had gathered to talk man talk and get the house heat up and running in the late hours. They were so grateful (I left them to their man talk of course), that I adopted it for any expected repairman.
Coffee for cold weather and lemonade for heat, unsweetened because diabetes here runs high. Nowadays I put it in the big stainless steel Thermos so it will be perfect whenever they want it.... I set out sugar and sweetener on the side, with a big man-size mug. And a fresh water bottle to take along when they go. If it's near mealtime I've been known to set out a thick-sliced sandwich, too. (In a baggie in case they want to take it along for later.) Sometimes in hot weather I've let them know it's set out on the big, cool front porch where there is a table and comfy chairs, especially if it's outside work they're doing.
Again, it's the way you do it that does the trick-- offers are always turned down, but wordless food gifts are always taken.
Anyway, word travels fast in these parts, and most everyone who comes here treats me right. And I've sure heard a lot of great stories, over that lemonade!