From Pistol-Training.com : Competition Pros and Cons

Competition: Pros and Cons

 

Some points of interest from the article and comments:

So, you need to be honest with yourself about your motivation. Are you there to supplement your training or are you there to compete for the sake of competition? Both are perfectly valid choices, obviously. But the answer to that question is going to have an impact on what you practice. Time you spend working on competition-oriented skills is time you could have used to work on defense-oriented skills.

Another potential snare of competition shooting for the defense-minded shooter is equipment selection. When you go to a match, it’s hard to look at the guys with their tricked out race gear when you’re wearing a Glock 27 in an IWB holster under a sweatshirt (which is exactly how I shot my first USPSA match in the mid-90s). The temptation to compromise a little here and a little there can be strong. First you switch to a G34… because, hey, it’s basically the same gun, right? But it’s not. Seeing how you can shoot with a G34 isn’t the same as seeing what you can do with a much smaller, greater recoiling G27. Then you switch to a faster holster. Now you’re practicing to draw a different way and perhaps from a different location on your body. We said earlier that people will focus more on the definitely-game this weekend than the maybe-fight in the future. So where will your focus be, on your CCW gear or your game gear? On the other hand, if you’re going to run your “real” gear you cannot use it as an excuse or a crutch. You’re making a decision and that’s 100% on you. Don’t try to convince yourself you would have beat the World Champion if only your holster was a little faster or your sight radius a little longer.

 From the comments section.

Stealing a quote from Soutnarc’s forum; “You can’t go as deep training as in a race or a fight. If you don’t compete it’s easy to convince yourself you’re going hard. You’re not.” Mark Twight
I do find that I have to be careful to not let bad habits get into my tactical toolbox, like standing in a doorway port at an IPSC match and just blazing away at targets to get max speed on the string of fire, or running balls-to-the-wall down a hallway at an IDPA match instead of moving as I would in real life.
I almost never win a local match, but I do well, and with IDPA I very often get “most accurate” at the match running a G19 with a NY1 trigger from an IWB holster under a T-shirt, instead of the “concealed carry” guns other guys are running, like a tricked G34 in a Blace Tech holster under a ‘shoot-me” vest.

 It's all about what you're there to get from it and being up front with yourself about it too.