you didn't say which auto loader in particular, and for different models there are different times that things need to be changed. however since you listed no specific model, i will give my xd service model as an example. i replace recoil spring and striker spring every 3,000rds, is this needed not necessarily alot depends on how hot of loads you are shooting, but to keep it the same across the board i stick with 3000rds. the striker spring i have let go as long as 8000, however now i replace it when i do the recoil spring.
mag springs, in carry mags, i replace them every 6 months, in training magazines, i change them when they fail me at the range.