Increasing weights while strength training

Started strong curves a few weeks ago and just curious how frequently to increase my weights. For each exercise there is a suggested range of reps. For maximal muscle gains and results, should the goal be to max out the reps (x3 sets) before increasing to a higher weight during the next exercise session? Or, if you can do at least the minimum number of suggested reps (x3 sets) then the next session is it ok to increase the weights?