When providing general advice, I typically use ranges that fall within the prejudices of our membership, as there are less rebuttals that sidetrack the conversation. Keep in mind there is more than 1 correct answer to most wine making questions, and we should all make our own informed decision. We can disagree without anyone being wrong.
But if you're asking what I do? Ok, keep a pinch of salt handy ...
For kits without skins or for fresh juice, first racking is between 1.000 and 1.010. I do not like to let fermentation complete in the primary, so I rack before then. Given that other priorities can interfere, I rack a bit early to ensure the fermentation is not complete. Fermentation will complete in the carboy.
Some let the fermentation complete, and some may let the wine rest even longer. I don't -- just not comfortable with that, based upon early training and experiences. I want a CO2 cushion at first racking.
For kits with skins or fresh grapes? I target 1.000 for the first racking. I want more skin contact, but also want a solid cap so I can rack free run wine from beneath it, as I run less plain 'ole wine through the press. My target is a happy medium. Again, others go to completion, and there is no problem with that.
At some point, things will not go the way you want. You may make a mistake, or Mother Nature may mess with you. Stuff happens.
Do your best and enjoy yourself! No matter what happens, someone else on this forum has already done it or experienced it. If something doesn't go as planned, help is available.
I've tossed wine that went bad. And I've had 5 gallons of cooking wine -- remember that a lot of faults are covered by boiling the wine as part of a sauce!