Another issue: get a water bottle cage that suits you. Fighting the cage tension to yank out a bottle and shove it back in can throw off your balance.

Some are way too tight, but most aluminum cages can safely be bent a bit to loosen an excessively tight grip. Can't really do that with plastic or carbon fiber, although the grippers can be filed down a bit.

I've switched bottle cages several times to find some I like. I use a cheap 50 Strong brand on the downtubes on both road bikes because they're easy to use and secure on the downtube. But they don't grip tightly enough to retain a full water bottle on the seat tube if I hit really hard ruts. I don't want to fall over my own water bottle or make someone else fall.

So for the seat tubes I use a Tacx Deva, which holds more securely -- a bit too securely for the downtube -- and looks better. But the cages are mismatched so I suppose it doesn't matter.