Every state and game seems to have its own clock, so I stopped trusting my memory. I put the draw date on the envelope and check the official rule if a ticket needs attention. What system keeps old tickets from disappearing on you?
Put three items on the envelope: issuing state, exact game and draw or purchase date. Then copy the deadline from that lottery's official claim page and add the date you checked it. Do not calculate every ticket from one national rule.
Powerball says its expiration period typically ranges from 90 days to one year depending on the selling jurisdiction. California, for example, generally allows 180 days for draw games but one year for a Powerball or Mega Millions jackpot. The ticket and current state page control, not these examples.