- Quality - is the shirt a brand you trust? If not, don't wear it. The shirt might be great but you don't want to test it on "the big day."
- Temperature - some race swag is bought because it's cheap, not practical. Given a t-shirt for a winter run in Chicago? Handed long sleeves in Death Valley? Wear the right sleeve length for the race temps, not the race director.
- Distance - I might wear new shoes, socks or a shirt for a short run but will fall back on proven favorites for longer races. Think about how long you would be ok being uncomfortable and then decide if you want to try something new or broken in.
- Team spirit - are you running with or for a team? You might need to suck it up and wear the shirt. Or have a reliable friend give you the team shirt at the finish. That way, your finisher photos rep the team and you stay comfy.
|Non-wicking, too-big race shirt|
Probably nothing major BUT, if the fabric doesn't breath, like this shirt I got in 2010, you may overheat and be slower than you like. If the seams under your arms are too tight, the fabric too bunchy or the shirt poorly crafted, you may take home some chafing along with your medal.
No matter what you wear, enjoy the race and pray for good swag!