Your plan never affects cards other people send you — receiving live updates is free and unlimited on every plan. What your plan sets is how many live cards you can have out at once: Free 5, Plus 15, Pro and Power no limit. See Sending a card that stays up to date for what counts.
If you move to a lower plan, or your subscription ends
Every live card you've already sent keeps updating. Nothing pauses, and nobody loses anything.
What changes is new shares: they go live only while you're under the new plan's limit. Past it, they go as snapshots, and the Ready to share step tells you before you send.
If you move up
The limit lifts straight away for new shares. Cards that already went as snapshots stay snapshots — upgrading can't turn them live — so re-share to anyone you want to keep updated.
On Pro or Power, Deeta shows Live updates are on with See snapshot shares, and each unaccepted snapshot link on Settings → Shared links has Re-share to enable live updates in its ••• menu.
Keeping an eye on it
Settings → Usage shows Live shares on Free and Plus: how many are claimed and how many are waiting.
Troubleshooting
A share I wanted live says Snapshot only. You'd used all your live cards when you sent it, or the set is set to Never, or Keep updated was off. Re-share once you have room.
I'm on Free and receiving updates fine. That's correct. Receiving is free and unlimited.
Questions
Does changing plan delete anything? No.
Are the people I share with affected when my plan changes? No. Cards you've already sent keep updating.
Can I pause my updates without changing plan? Not with one switch. Use Stop updating per person in Who has your profile, or per set in Settings → Deet Sets.