Larry:

This it true of some battery chemistries, but not lead-acid batteries. If
you treat them that way, you will get a rather short service life from them.
AGM batteries are somewhat more tolerant of deep discharge, but sulfation
is still an issue. For best life with lead-acid batteries of any type,
discharge them to no mor than about 50%, and charge immediately after use.
Go to any of the battery manufacturer's sites, and the information you find
there will bear this out.