During the cold winter months pool water tends to stay clear with very little help. Generally algae does not appear and I hardly ever see a pool turn green. Any algae growth that does occur is extremely slow.
Of course winterizing is ideal, but many of our pools are not winterized. To these we add an occasional dose of chlorine and run the pump at least once a week. Vacuuming requirements are negligible – once every 3 or 4 weeks is plenty under normal circumstances.
Winterized pools? We cover them and forget them until April or May, which is so much easier.
At the end of the day it is the pool owner who makes the decision and either way we are happy; our pools are always clear and blue.