Yes, it is part of their skill set, so they should learn how and when to use it — much like any other skill.
Planning Life Taps also helps with DPS (glyph) and survivability.
I really dislike locks who, due to poor planning, tap themselves to near death mid-fight right before AoE hits and other shenanigans.
Regarding HoTs, my most common experience is:
The fight ends, and the party is moving to the next group. I see the lock is below half mana, so I put a HoT on them.
They proceed to ignore it, even though they don't have anything else to do. The HoT expires, so I just wasted mana for nothing.
Then they tap themselves to near death when the next group is pulled and expect (some even yell for) healing...
Also, I don't see a reason why they shouldn't use food/drinks when the healer (and possibly the rest of the party) is drinking or standing still.
Why do they wait for the healer to replenish mana and then expect to be healed?
This is especially annoying at low levels when you have a mana pool for like 6–7 heals—but at least then I can assume they’re new to WoW or the class.
Since this thread is about overall healer experience, not just a rant about locks, I’ll add some other stuff and the frequency I encounter it:
3/10 RDFs
Headless or Rambo tanks, oblivious to their surroundings, actual gear, or the party's GS average.
3/10 RDFs
DPS eating cleaves for no reason.
2/10 RDFs
Hunters using Aspect of the Pack or Distracting Shot.
2/10 RDFs
DPS trying to go “faster” by pre-pulling additional groups—either for the poor 3k GS tank or when I’m out of mana and the tank actually waits for me.
2/10 RDFs
Some 6k+ clothie showing off their "imba" DPS while standing in melee range or just flexing on the 5k tank.
1/20 RDFs
Fresh 80s boosting their GS/iLvl via BoEs not meant for their class/spec.
Yes, I’ve seen a warrior with cloth shoulders, healer mail legs, and a healer plate belt. Obviously, no gems or enchants either.
1/30 RDFs
Ridiculously low DPS. If I can out-DPS them on a single target as a healer, something is very wrong.
Some issues can be solved by kicking the culprit or just wiping once, but in general, I’ve left the group like 5–7 times while leveling and RHC-gearing each character.
After all, it’s a game and should be fun—not another job where ungrateful people undermine your efforts and then yell at you when you don’t perform miracles at will.