How long can 1Password 8 be used offline?

Hello STFLX,

Thanks for your question. As mentioned, your locally stored cache includes the data from your 1Password account as of the last time you connected to 1Password.com. It can be used offline indefinitely. However, any changes made to items on either your PC or iOS device will not sync to 1Password.com (and out to the other devices using the account). We recommend using 1Password online on a regular basis to ensure the accurate syncing of items across all devices and to check for updates to the application.

I hope this helps but please let us know if you have any other questions.