No, there is no single limit to the length of time.
Registries typically have an event date assigned, often a wedding date. An "event" date is not required -- if the client is just crowdfunding a down payment, this becomes the 'target date' or goal.
By policy, registries may be purged at 180-days from the event date but may be shortened or extended.
The standard operating procedure recommends Archiving the registry before Deletion. It's also recommended to download Contribution and Pledge history for home purchase planning.
