I use the straight boric acid powder from the drug store (it's stronger, that's why it more expensive).
We have very little freezing weather to cut down the bug population, so they are a problem that never completely disappears. Boric Acid works better than anything else I've tried, but there are certain ways to use it that makes it more affective.
Always "dust" the areas to be protected, piles or mounds of the powder are easily avoided by insects.
The idea is to get the critters to walk through it, not walk around it.
For ants, I make a baited container with some kind of lid to make it
water and rain proof. In this box you will cut or punch tiny holes just large enough for the bugs to gain access to the bait (a bottle cap full of granulated sugar works well), which is placed in the middle of the container. Around the bait, you DUST the powdered Boric Acid.
The ants have to crawl through it to carry off the grains of sugar
and their populations are soon severely depleted.
In the house I dust contertops, inside cabinets, under sinks, under and around appliances and the floor of any bathrooms with the acid powder. This is done for roaches.
Twice a year I spray the foundation of my house with a pressurized sprayer containing a mixture of Diazinon (16 oz.), Creosote (2 oz.) and tap water (1 gal.). The combination of treatments eliminate about 99%
of my bug problems. 8)