Judging by these posts, I must be the only hacker that actually likes going to the range. Extremely relaxing, I find, and generally more instructive at my low level than the all-too-frequent 270-yd drive into the woods that I will uncork on the course.
I usually hit around 140 balls at a visit, which is four small buckets of 35--but there is always a plan. At least one of the four is dedicated solely to approach shots with a 8i or less, hitting at the near clump of flags (90-155). One bucket will usually be devoted to a new club (if any) or one that I haven't hit much lately to try and build confidence in it--this week that was 3W off the deck. The rest is split between 5, 6 or 7i for general swing practice and working on specific things. Usually, I take notes after every round of the things that I do wrong, particularly if I do them wrong repeatedly, and try to work on those in a deliberate way. For instance, normally I fight a hook, but last Sunday for some reason was pushing (not slicing) everything to the right off the tee. That warranted a full bucket on Tuesday until it was fixed (though, alas, "fixed" means back to a pronounced draw that likes to turn into a hook--well, there's always tomorrow!). Lastly, my teaching pro often gives me "homework" between lessons, and that gets a fair amount of time.
Regardless of whatever else I do, I always end with chip/putt.