before cycle - so you have baselines. beyond that, it depends on your $$. best would be if you are doing orals just at last day of pct, and then 45 days later. on injectibles at end of cycle, last of pct, 60 later.
minimally before cycle and given the choice i'd go with 30 days after end of pct if you are only getting a second and not a 3rd.