If you choose RFQ checkout then it is the same as WooCommerce cart. You can change that also: Ref: https://woo.com/document/change-the-default-cart-session-length/
If you choose normal checkout, the default is one day, but you can increase it to 30 days in the “quote request page” tab and set it to 30 days. Set it to cookies to make sure the server does not expire PHP sessions. This is sliding, meaning every time user visits the site, the session gets extended. So you probably need only a few days.
Please note, at the moment, you can’t save different versions for later, just the one you are currently working on.