In Order Settings in Admin, there is a section called Storage Control. This is where you can manage re-orders, saved projects and saved baskets / carts. 

You can allow customers to order previous orders (re-orders) and you can control how far back they can order. By default this is set to 400 days as we have number of customers selling calendars once per year, however you can change this: 

Following on from this you have Saved Projects and Saved Baskets - as per the below they're disabled by default, but you can enable them here: 

As per the instructions, it is important to enable the associated Email Message Templates for these. If you don't, then projects and baskets will expire without warning the end user. 

The last two settings in this section control when the aforementioned email message templates are sent (the number of days prior to basket / project expiring):