32-Oz CamelBak Chute Mag Vacuum Insulated Stainless Steel Water Bottle (Black) Expired

Daily deep cleaning is unnecessary, but once you have the process down it should take less than 10 minutes including popping out the gaskets to give a thorough swabbing (add 10 minutes if you want to do an optional vinegar soak after scrubbing off any residue). If you only keep drinking water in the bottle, keep the openings lidded when not in use, and don't do any intentional backwashing, you can use the bottle continuously (without ever emptying the bottle) for maybe 4-6 weeks between deep cleaning.

While optional, you can do shorter cleans in between by emptying the bottle, putting in a little soapy water and swishing it around (or use a bottle brush to give a quick inside scrub), and do a quick sponge wash around the screw threads on all lids, takes less than a couple minutes. Rinse and if you can, dry it (a second bottle helps for rotation).

The main issue with metal bottles is the (removable gasket) and lid threads (both sides). The gaskets because moisture can get trapped where the gasket seats, so there's a whole hidden side that can grow mildew, and you have to pop the gasket out to clean there. The lid threads, particularly at the drinking spout, because it's right next to where people touch their lips to drink so microbes collect most easily there.

You can pop the gaskets out with a couple quick taps of the lid onto a padded hard surface, or you can use a toothpick or similar to pry them out. Then use a brush or swab with soapy water to scrub out where the gasket sits, and around any lid screw threads (both sides), as well as cleaning the gasket itself. If you're going to soak with vinegar (10 minutes is enough), you should pop the gaskets out as well since you'll want to remove residue/mildew first anyway.

You don't need to fit your hand in the bottle, the inside of the bottle is pretty low on the list of mildew risk (much lower compared to the gasket areas and screw threading for the lids). You should still get a bottle brush/sponge that can reach all over the inside of the bottle though.