base building necessary?

[pinnipedestrian]

im not very far in the game yet so i am just wondering if there are missions where its required or if I can just not. is it more useful later on because besides the replenishing supplies one i dont really see it as worth it?

[Can I pet that dawg]

Hmm, in some missions for sure you'll have to build bases. But other than that, they're not necessary. I rarely build them, unless mission requires it.
I'd say Attack Base is also very useful. The more you have, the more extra damages you do. Same goes for Bomb Base, there are few mission in Territory Recovery Mode when it'll just be very useful. But the rest isn't necessary, really, you can go without them.
They're a bit more useful later, on beginning levels they aren't helpful. Here the most useful is Supply Base and the one I can't remember the name, but it's automatically shooting at closing titans. But also remember to upgrade them! They're getting better with that.