Strange axles will usually show spline twisting before the axle out right breaks. Do you have any problems pulling the axles out, if they slide out nice it should be fine. If they are difficult they are probably twisting and you may want to upgrade.
What type of trans do you run, how much you are shocking things plays a part as well.
The axles check OK for now with a Hoosier 315 and a 1.80 glide.
Just considering a another gear set 4.00:1 and another 3rd member. The cheaper way is keep a 35 spool or go 40 plus new axles shorten housing ends -2"per side for a better rim off set so i can run double bead locks.