falseif you try to access them after that.
This TTL mechanism is ideal for a lot of simple caching needs: Say you want to cache a calculated value, but you want the cache to be renewed each hour, to keep the calculation in the value relatively up to date. You would store the value in cache with a TTL of one hour, and every time you need to access that value, you would check first if it's in cache. If it is, you use the cached value. If it's not, you calculate a new value and then store it in cache, again with a one hour TTL.
As a general rule, do not use cache systems to store persistent information. Use a database instead.