I find training rides are useful for pushing me a little harder than I would normally go. It helps me to gain fitness otherwise I am tempted to stay in my 'comfort' zone. I like to ride with people who are faster than me, it gives me something to work towards. I do plan to do a few races this summer It doesn't have to be that your are training for an event to go to training rides though. They typically are around 20 miles, some here are around 10 as they factor in the hill routes too. I haven't had the nerve to try one of those yet. Most of them are graded so you know what pace the group typically goes and pick one to match you mood.