Once my hair reaches my neck, I get annoyed with it. I'd guess maybe every 1.5-2 months, if possible. I used to have hair down to my hips, but I'd go nuts if I ever went back to that. Got to have it short and out of the way.
I don't spend much on haircare at all; like I've said, my hair is quite short, so the large shampoo/conditioner bottles can easily last a whole year. I've got some gel for spiking it, some hair paint, and some purple dye, but I don't use them often, so they last a long time, too. Plus, I think all of those products were gifts. ._.;
Mostly, I just stick to washing it and letting it be. I hate spending lots of time, energy, or money on my hair. D|