[HTML5 Games] How long do save files (local storage) persist for?

I noticed that for some of the HTML5 Construct games I played a month or 2 ago my save data is gone and I'm back at the start. Just wondering, how long do save files usually last and what determines it? Is it the users browser cookie settings? Anything we can do to make them last longer?

Localstorage should last forever, barring a significant update to the game that changes how saves are handled, reinstalling the browser (or changing browsers/computers), or manually clearing the browser cache. It is related to the "Cookies and other site data" option under the clear browsing data options in Chrome.

For persistent storage, your best option is to use a cloud service or your own server to sync user data online in addition to using local storage.

Alternatively, if your game is packaged as an app or executable, it should be significantly more difficult for localstorage to be unintentionally cleared.