different per plant or under a new light etc... familiarity with how deeply you produce the type of nugs you want to produce should dictate. I try to err on leaving a little extra, but there is a lot less work if you minimize the larf and other substandard levels in canopy.
Some plants will bush out and nothing we can do, others will result in nice long stalks of buds with limited branching. the latter are the ones i'd lollipop less, as those axillary buds will merge together to form long buds along stem vs. branching out and creating many small colas and larf down below => lots of extra work trimming. But, if you lollipop too much, you'll severely impact yield on the type that branch out uncontrollably.
Familiarity with how long they stretch under 12-12 is helpful too... again, i try to err on the conservative side and the 'next' run i'll adjust in a more precise way.
Leave the leaves! when you lollipop, leave them behind... the plant will suck them dry and shed them -> i.e. useful to the plant. I do remove the ones that get in the way of easy watering.