Should I store Shopify Checkout ID in localstorage or cookie? --React Storefront

I’m creating a shopify storefront using react, and I want to store the checkout ID (returned from shopify) in either cookies, localstorage, or session storage so that when an unlogged in user returns to the site shortly after shopping, I can make a call to get the current checkout from the ID (checkout includes current cart), and populate their cart.

I haven’t been able to get a clear answer on what is standard/the better option here. I’ve seen store with both, and I know shopify uses cookies to start a cartID (not from their api), but they are in a different situation than a storefront.

Thanks all!