The problem with baits and chemical stuff is that they build up resistance to them.
When we lived in France we were told to use lemon juice and so when we had ants arrive here in sgp we dripped lemon juice on them and rubbed it on the cup*** following their tracks as much as poss.
It took a couple of goes but no ants in the 6 months since! (by the way, the lemon juice burns them so they don't come back)
We also got little mites in our boxes of flour and so since then keep all loose dry foods in plastic containers. Tupperware thinks we are their best client...