Google failed us: We can’t find any official stats, but if we had to place a bet, we’d put our money on October being the month in which the most people run a half-marathon or marathon.

One thing we do know for sure: It’s easy to forget something when packing for an away-race. (AMR co-founder Sarah still kicks herself for leaving her GPS watch at home when she flew to San Francisco for a half…more than a decade ago!) To do you a solid, we put together a checklist of gear to pack for a half-marathon or marathon.

Download it, print it, then put pen to paper as you pack to ensure you have everything you need on the starting line. We bet you’ll be glad you did!