No, your favURL page does not expire. Once it is generated, it stays live for free, with no time limit and no card on file. You do not have to upgrade to keep it.
Free forever, not a free trial
favURL is not a trial that locks your page after 30 days. The free plan is permanent. Your page keeps serving visitors, showing your reviews, photos, hours, and links, for as long as you want it up.
What happens if you never upgrade
Nothing changes. You keep the full free page described in is favURL free. Paid plans only add optional extras like a custom domain or removing branding, and skipping them does not affect whether your page stays online.
What happens if you cancel a paid plan
If you upgrade and later cancel, your page does not disappear. It simply returns to the free plan: the optional extras you paid for switch off, and the core page keeps working exactly as before.
The one thing that matters
Your page is built from your Google listing, so as long as your business exists on Google with reviews, favURL can keep your page current. If you ever want to take it down, you stay in control: you can unpublish or delete it from your dashboard at any time.