@dbrn32 makes a very good point here, I regularly see the same thing on the forums.
Many think they are about to harvest and a month goes by which ends up causing deficiencys and lack of finished bud growth.
I would say feed till the end until you have more experience under your belt, with harvesting as well as with a specific strain. Then you can more accurately predict what’s going to happen in what time frame you can cut nutrients and do a flush, test it against non flushed and see which you prefer.
I personally don’t flush, I rarely grow the same genetics so it’s hard to predict what my plants are for sure going to do as some take along time to build Amber (and I love indica that puts you in da couch) as well I personally can’t tell a difference, nor have I seen any scientific evidence or even large scale test testing to prove flushing is worth it. Although it would save money on nutrients so if I grew a strain over and over again then I would probably run water at the end.