As stated above, there’s different perspectives.
The way I see sand beds is that they’re essentially litter boxes. If you have a few fish, then it’s probably not important but if you have a lot of things that produce waste, that waste is just going to collect and collect until your sand beds microorganisms and detrivores are going to be out competed. I take a Turkey baster about once every 2-3 months and blow into my 2-3” sand bed… you should see the crap that comes out of it.
I have a large system with a lot of water volume, so I don’t have to worry about my tank water becoming toxic if I clean too much of the sand at once. Something to consider though and depending on your setup, you may want to clean your sand in sections at a time