Starting to show some restraint.

Eventually it seems that couples want to try some bondage when they've been together for long enough and feel the need to try something new. Two things almost immediately leap to the fore of their brains; silk scarves and handcuffs.

Silk scarves seem totally non-threatening and romantic. It smacks of romance novels and rich chocolates. Sadly, most people on the street couldn't tie a decent knot to save their life. Which helps explain why so many people die from falls. Anyway, the other thing that many of these adventurous couples tend to be unaware of is that silk is a very fine fiber and it can and will bind down hideously tight in the right conditions. With the wrong knot, the sexual escapade could end with nerve damage and cut-off blood flow. Unless you're prepared to cut them out of the scarves, it's risking more trauma than fun.

Or there are hand-cuffs. Everyone's heard of those. It has some visceral impact to it. Très naughty. Of course hand-cuffs weren't really designed to be used for sex. The bracelets are narrow and since metal is rumored to be less than yielding to flesh, one might expect the potential for bruising, nerve damage or other damage to be somewhat elevated. If you buy cheap, they'll often be made of pressed thin gauge metal with a lever-lock. The quality is low so their potential to injure is going to be very high if used for anything more than window-dressing. The levers are too easily bumped allowing the bracelets to tighten. The chain links may part suddenly. The metal might shear at an inconvenient moment.
Higher quality provides less potential for materials failure. A recessed double lock mechanism will keep the bracelets from clamping down if set and it's difficult to accidentally disengage them. You'd still not want to try an Olympic parallel rings routine on them though. On the other hand, should you lose the key, you're going to have a bitch of time cutting through the hardened metal. Even more so if you are disinclined to mangle your captive lover's wrist(s) in the process.