When to replace bag gloves?

I've got a pair of Ringside Super Bag Gloves. Have had them for about 3 years. Once a week they get used on pads and heavy bag. They aren't visibly misshapen (doesn't really look like padding has shifted).

In the interest of protecting my rapidly aging and often troublesome joints, is it a good idea to go ahead and replace them even if they basically still look and feel OK?

Good advice. I will pay more attention to wrapping properly. Many thanks, Martin.

You've had them for 3 years and the padding isn't all busted up?!?!