I’d say enjoy it while you can.
But guaranfuckingteed you will run into problems with 1500 eventually.
Your doc seems like the most awesomest doc ever, letting you chill in the cycle-zone long term.
But your cholesterol will get gnarly, your red blood cell/hematocrit count will get too high, and those two together is like asking pretty please for a blood clot or heart attack, among other complications.
1000 is a supraphysiological value to chill at for a while, everyone is different. I’ve been hovering 1100-1200 for a few years and my bloodwork is starting to get slightly undesirable.
Just know high end of normal you could live a long life, outside of that range too long, and you may end up with problems down the road. The kind that sneak up on you too if you aren’t checking bloodwork 4x a year