When do i need consider flushing i read i have to ...

I would def consider flushing for 2 weeks if it was me. With bottled nutes you get a lot of salt build up from synthetic nutes. I did an experiment with just soil and bottled nutes, and just “did a grow” with it with a plant and when I get the soil out of the pots it was just soil white and crystallized to the point it didn’t look like soil. I used GH trio. I’ve also seen this in a buddy’s grow where the smart pots on the outside were solid white on black pots and he was using “organic” bottled nutes. It wasn’t fit to smoke in my eyes. I read somewhere that when you start flushing break a tip of the leaf off and just taste the juice in the leaf if it taste bitter and nasty needs more flushing. I know the GH says to flush after every third feeding. Personally I would take the 2 weeks to flush what ever you decide good luck with your harvest and happy growing!