I've been doing it that way for a decade with good success. I use brown glass bottles with tight-fitting lids and keep them away from direct sunlight (though I don't know for sure that this is necessary). 5 or 6 rolls is a very conservative estimate. More like 8 or 10. Be very careful not to cross contaminate. I'm obsessive about this, having seen how quickly a drop of blix will spoil a bottle of developer. I have separate beakers for mixing up, separate stirring sticks and a thermometer that only goes into the developer. (And another one that monitors the warming bath; you don't need to monitor the blix temp too closely.) This equipment isn't very expensive and it lasts forever. You can get a plastic tub at the dollar store for your warming bath.
If you're unsure about the viability of your dev, keep a roll of expired color film for doing clip tests. As the dev gets nearer to what you reckon might be its demise, cut off a couple of inches of test film and leave it in direct sunlight for several minutes, then develop it as normal. It should come out almost black (very very dark brown) if the chemistry is still good.
C-41 is a bit more complicated than b&w but not much. Do some practice runs on rolls that you don't care too much about and once you get a routine going that works for you, you'll find you can do color developing without any stress and quite efficiently, I would recommend starting out with a two-bath kit like Unicolor or FPP and moving up to separate bleach and fix after you've mastered the basics.