I've always reused the same pin with older wider chains. And I just did it with my new shimano 11 speed chain I just put on with my other new toys for my bike. They only give you one of the pins to connect the chain with and after installing the first time and breaking the stub off, I realized the chain was too long. Being late Saturday, I wasn't going to be able to get another, so with some difficulty I was able to press that tiny thing back in.
I found a large pair of vice grips is the key to getting it started straight. Along with patience, lots of light and strong glasses if you have old eyes like me.
300 plus miles so far and no issues. If I had a lot of power in my legs I might have played it safe and waited to get a new one. I will be adding some of those pins to my spare parts though, if I ever remember them when I'm where I can get them.
Not big on master links either. They add width to the link and I'd think Shimano would give me one if they thought there wasn't any chance they might occasionally interfere with things.