Customer called for a recharge of a fire extinguisher. Upon arrival I found that the Annual was due also so I talked to them and we decided to do this while I was there. I found that there were several that needed to be hydrotested and a couple that needed to have a 6 year maintenance. I completed this task and rehung all the fire extinguishers in their proper place. I let the customer know that this was to be done annually. I also let them know that I work frequently in their area and can stop by if they have any other needs.