I would say to cash some out when it hits $1,000,000 but you might not need to since everyone will be accepting it soon.
What do you mean by you might not need to? First things first, bitcoin hitting that kind of zeros will take 50 years atlas. Though bitcoin is powerful it doesn't mean it will hit that price in our lifetime. Everyone will accept it and the price will increase thats okay but there will be limit for that too. Bitcoin will last forever which is completely different thinking but bitcoin hitting and getting accepted at 1B is very different stuff.
Bitcoins will definitely last forever but the time frame at which they will touch the specified amount is not known yet. Bitcoins are very potential and I don’t figure out any single reason for not touching this target.