I dyed my hair once every 3-4 weeks for over 8 years... and honestly, all the chemicals ruined the texture of my hair. It used to have curls and it used to bounce and have life... but now it's flat, dry, extremely porous... and I used extremely gentle hair dyes. I guess it depends on your hair. As most of the ladies here know, I'm Sicilian... I don't have sleek or shiny hair naturally (I have a dry, course texture) so my hair may have already been too dry to use color. However, if you feel that your hair can handle it, go for it. Rinse the dye after 20 or so minutes... don't leave it on for 45 minutes like the box says. Deep condition often (2x a week) and seal with EVOO. Hope this helps!
EDIT: Some of my hair is so thin that you can see through it. Other strands are thick, course, and have very tight Z-shaped curls. Eventually, your hair gets so porous that the dyes don't even stick anymore... so I have some strands with literally no pigment! Not trying to deter you... but seriously be careful and consider organic dyes.