It's a double edged sword though isn't it, Yes retirement must have been an attractive thought but when you've spent your whole life in the legions surrounded by soldiers (obviously) following strict rules and regulations, the thought of going it alone would also have been an extremely terrifying thought too.
Plus if you've reached the ripe old age of 50+ then you would expect to have reached a pretty decent rank which would excuse you from the majority of the hardships related to life in the legions, so life may not be as tough as you think. You'd have the power and authority that goes with your rank plus you'd have the respect of the younger and lesser soldiers. Where as if you left the legions you'd just be another civilian just like the rest.
That was my main point from the beginning, retiring might not be easy when you were used to one way of living,with the respect that came from your experience. At the same time, I believe that most soldiers that survived their service did retire at some point.
I wish I had time to read it, but for my I focus on visiting as many museums and sites as possible, there will b time to read soon enough.
Anyway about the pay, surly there was some surplus? I have a difficult time believing that the soldiers came out +/- 0.