People often envision a permanent bracelet that fits just next to the skin without moving anywhere. This is a tricky fit to achieve without having the bracelet tug or pull against the skin. Any puffiness you experience from salt, sugar, alcohol, heat, exercise and sleep will affect the comfort of a bracelet that's too tight. A bracelet too tight is under pressure which may cause it to stretch or break.
Sometimes people like a looser fit. This solves the problem of a bracelet that's constricting while increasing the possibility that the bracelet will be caught, snagged or pulled. All these things contribute to a braclet stretching and increases the probability of a bracelet breaking.
I love to have about a finger space between the chain and the bracelet for the most comfortable fit. Of course link size and link shape play a role in the best size.
Let's take a look at the array of bracelets I have on one of my arms as an example. I wear each of these styles for demonstration purposes.
From left to right:
The bracelet on the left is way too tight. This one hits snug to my arm. I can get a finger in between my bracelet and my wrist but only when I pull into my skin.
The next, small paperclip style chaing is the exact right fit. It hangs just below my wrist and I can comfortably have one fingerspace fit just under the chain. This length allows my chain to move freely and doesn't squeeze when I bend, flex, grasp or move my wrist. It's not easy to catch on things and runs a smaller risk of stretching, getting caught in something and breaking.
Just to the right of that are two other chains, a heart chain and a larger paperclip. Both these have a little more room than I like to see. There's enough space to fit my first two fingers through the gap. I haven't caught them on anything but I know I have to be careful when wearing winter gloves, cleaning gloves or other support gloves used in fitness activities.
Last is the one chain I've been wearing for over 1 year. This was my very first sterling silver bracelet "tester" It's been around a while and is longer than ideal. This chain has the biggest gap. If I were wearing only this chain, it would be the one most likely to catch and break. Because this bracelet is so long, there's an added problem. The amethyst gem I wear on that bracelet runs the risk of cracking if it swings up against a table or another surface during wear.
Ultimately the fit you have is going to be based on a combination of your personal preference and the recommendation of the permanent jewelry artist. When you're getting your permanent bracelet, be sure consider what your permanent jewelry artist recommends to have the best experience and longest possible wear with your permanent jewelry piece.