I usually work with a partner so I only carry one set of handcuffs on my person. I carry one or two additional sets inside my gear bag. Years ago when I works alone, I carried two sets of handcuffs and two sets of Zip Cuffs. My handcuffs are carried on my strong side, behind my firearm. I don’t anticipate having my gun drawn and having to handcuff someone one handed with my left hand, so I wear the on my right side.
It is important to inspect your handcuffs at least once a month if you don’t use them much. Make sure they are clean; it’s not hard to get fuzz and lint inside the case. Check them for rust and if there is any, clean them as you would your handgun. Generally you don’t need to oil your handcuffs, but if you do a tiny drop inside the keyway should be good for at least a year.
When I carried two sets of handcuffs, I carried them in separate, identical handcuff cases. The double handcuff case is uncomfortable to sit on. Hinged handcuffs are stronger than those with a chain but are not generally necessary. If you are arresting many violent mental or drug suspects they are a good idea but I would not carry them as my only set of handcuffs. Flexible nylon cuffs are a good tool for arresting people with a cast on their arm or other mobility issues. Keep them secure, that’s what the SGT Says.