Is it necessary to apply lotion to your hands after washing each time?

If you are talking about applying antibacterial lotion
after following proper handwashing procedures then I would say no. The skin has natural
oils that help to keep the skin moisturized.

The CDC has a
procedure that should be followed when washing your hands. They recommend applying soap
to the hands and working up a lather, using warm water if possible. Hands should be
scrubbed for at least 15-20 seconds. Dry hands with a paper towel or hand dryer. Also,
use the towel to turn off the faucet to prevent the spread of
germs.

If you are talking about applying lotion in general
then it depends on whether your skin is dry or not. I find that I need to apply more
lotion in the colder months. Otherwise my hands tend to get very
dry.