Finding ants in most rooms of my house

Has there been any heavy rain or flooding around your house lately?

Terro is a cheap easy solution but they are a carbohydrate bait and depending on the time of year and the ant's current needs they may not partake heavily. If they don't work then I would try a protein-based bait. If you really have a serious infestation that you want to get rid of fast I would use both a carb based pesticide (gel) and a protein based pesticide (granular) at the same time. They make dual sided bait plates you can bait yourself with both, I am not sure if anyone makes a ready to use dual plate pesticide bait station. That being said I have never had Advion (a gel) not work by itself. We get them at the camp sometimes when it rains a lot or floods.

One thing to note is to always use baits instead of sprays. The sprays kill too fast and the ants don't return to the colony. When an ant dies the body is eaten by the other ants so using baits takes the insecticide directly to the colony.

Another thing to note is if you have consistent problems putting granular based bait stations out consistently is a good idea. The gels/liquids dry out and don't attract the ants as well. The granular ones will just sit there until the decide to come in the house for groceries.

I've used Terro before when we had an actual colony coming in for food. It worked amazingly. But right now i've got just one or two ants roaming around.

Look up Borax and sugar for killing ants