Yeah. It's easy to get it out.

Not! 300 pounds of wet sand is a pain to mess with! Plus, on a filter of that age, the chances of cracking a lateral (separate the water from the sand at the bottom of the filter) is very high.

If the filter is keeping the water clear, it's working! Don't fix it!

If you want to test it, you can get some DE filter powder and add a couple of cups to the skimmer. If powder shoots back into the pool, via one of the returns, the filter needs service.