[caption id="" align="alignright" width="300"] Photograph of a chain-drive garage door opener. This residential unit is manufactured by The Chamberlain Group, Inc. under the LiftMaster brand name. (Photo credit: Wikipedia)[/caption] When was the last time you thought about your garage door or its automatic opener? Right, thought so. Like any mechanical system, the door and opener need some periodic, preventative maintenance. If you live in an area of frequent thunderstorms, a tight, well...