They do b/w and u/s. B/W to check P4 and E2 to make sure that levels are appropriate to their standards and if not, make medication adjustments. U/S to make sure that your uterine lining has changed patterns. They definitely do this after IVF cycles and would normally request it even for TI cycles, at least initially.
It's a matter of philosophy. Some REs feel that this is unnecessary.