Unlike Pebble Tec, Plaster pools need constant moisture in order to remain stable. Which means it would be a bad idea to drain a plaster pool in the middle of an Arizona summer. Doing so could cause the plaster to crack or pop, making it a very costly drain.
If the pool plaster is very old, it may be best to wait until your ready to remodel the plaster, instead of chancing it with a drain.
Is your pool too old to drain? At Blue Iguana Pools, we do not drain any plaster pools over 8 years old unless we deal it to be suitable for a drain. We also do not drain a plaster pool when the temperature is over 75 degrees. As a rule of thumb we do our best not to drain any type of pool during the summer unless absolutely necessary because of how damaging the hot sun can be to pool plaster.