I hate to say this but if you are dent them really fast after you are getting them you are probably just hitting them way to hard.
It could have somthing to do with how you have them set up but I would say only if youare stiking them at and angle and I mean like the heads are going strait up and down and would look flat when you are sitting behind the set.
as I have always told my students set the toms up so that you are comfertbale playing them. but would say that you are just playing really hard on them and I say that because I used to do it and I would eat thru some heads.
even now I still go thru snare heads quick and I only get about 1-2 months out of them and I know it's because I am playing to hard.
but about the only head I have had really good luck with is the
remo pin stripe
but Im sure that others will recomend to you other brands but Im just saying that I tryed a lot of them and those where the ones I had the most luck with untill I learned to stop playing so hard.
but like I said there could be other reasons that they are denting so easly but thats the forst thing that comes to my mind.