Magento – What settings control how long the products stay in cart for guests

At the moment most of our customers are guests (we do no require accounts)

Very often when customers returns to our website they see empty cart page (verified by testing and screen recording tools)

What settings control how long the products stay in cart for guests?

UPDATE: The question was marked as duplicate. But increasing sessions are not the only way to control how long the products stay in the cart.

Did some researching and find out couple of things that might be helpful to your guys.

1. DEFAULT magento persistent cart works a little bit different from what we would expect:

   • "persistent_shopping_cart cookie is only set on login and logout, and used for the "remember me" feature to automatically log in customers."
   • Here is more on that:
     • What does "Persistent Shopping Cart" do?
     • Does Persistent Shopping Cart work for guest (unlogged) visitors?

2. Like here was suggested you can control how long products stay in cart with sessions, but there are cons to that.

3. There is solution which helps you control this with cookies.

   • https://www.magentocommerce.com/magento-connect/persistent-guest-cart.html
   • https://github.com/clockworkgeek/Magento-Guest-Cookies

The create of the solution, Daniel, was kind enough to reply my email and commented on pros and cons in achieving higher ‘cart time’ for guests by increasing sessions time vs using your guest persistent cart extension.

Here is what he wrote:

"If session times are increased then all sorts of extra data about a
user is stored, like the last product they looked at and what filters
are used on category pages, and probably much more besides that.
Unfortunately each session is another file on the server and a busy
server with millions/billions of files could exceed it's "inode
limit". In a worse case scenario someone could use this to DDOS a
server gradually until it is unable to create new files and all sorts
of things break.

If my extension is used less information is stored (which might be
less useful) and no extra files are required. The hypothetical server
wouldn't "fill up" as quickly. Furthermore, if only the 'recently
viewed products' feature is used then nothing more is stored on the
server and there is no limit to the number of guests. Lastly my
extension only adds a cookie if there is something in the cart whereas
a session cookie is added for every user regardless."