Well Jenn you’ll just have to try your 3 Inf recaptures in our game, and see how they work - it’s something I’ve been thinking about too, and Darth has started doing it in my game with him. I can still retake, but it does require a bigger commitment than a 1 Inf garrison.
If you stick 1 infantry in each of 3 territories, if I attempt to counter with 1 infantry and 1 fighter each, there is an excellent chance of one or two of the battles failing. If I attempt to counter with 2 infantry and 1 fighter each, there is still a decent chance of at least one battle failing.
If you stick 3 infantry in 1 territory, I can use 4 infantry and 2 fighters, and there’s a good chance that the attacker wins. With 3 fighters, or 5 inf, there is an excellent chance.
So I can either be forced to send 6 inf 3 fighters for a lot of somewhat risky battles, or 4 infantry 2 fighters for one low-risk battle, or even send 1 more infantry or fighter in the latter case for almost certain success.
There are times and places to put more than 1 infantry in a lightly held territory, but I wouldn’t recommend it as general practice.