Agree with all that has been posted (except not cleaning them for 3 years). I use the all white ones and they come apart easily. I also replace my spigots periodically - they are cheap and not worth the risk if they are getting old IMO.
In fact, I take it a step further - I use bottling buckets for my fermenters - makes yeast harvesting spectacularly easy - think really cheap conical.
I disassemble the spigot after use, pbw, starsan and put away taken apart. When it is time to use them, I put the bucket and disassembled spigot in a tub I keep my starsan in while I am brewing. Probably sits in there 30 min. I reassemble the spigot under water and put it in the bucket underwater. Turn Bucket upside down for a time to get starsan on top half of bucket. As beer is chilling - resubmerge the spigot part, swirl starsan around one last time, lean bucket upside down on counter against the wall. Close spigot. Put plastic baggie over spigot with twist tie to keep things out during fermentation period. (some spigots need to be turned slightly so they don't hit floor when bucket is sitting flat.)
On bottling day, set bucket on counter. Take baggie off - spray spigot thoroughly with starsan just in case. Attach tubing to drain into keg. Take airlock out. Drain. Have mason jar in star san. Swirl up yeast from bottom of bucket and drain into a mason jar or two through the spigot. Cap, label and put in fridge. Disassemble bottling bucket. Clean and repeat.