I didn't realize there were a gazillion thru axles

[Mark McM]

Originally Posted by Jaybee

Maybe not as idiot proof as having the QR retained, but it's not that hard to develop a habit of always rethreading the TA a few turns back into the frame or fork. I've forgotten my helmet or shoes way more (once or twice) than I've lost my TA (never).

Not only does screwing the thru axle back in prevent it from being lost, but it also helps prevent damage to the fork/rear triangle in case of excessive side load during transport. It is common practice for thru axles to be installed when bare frames (or complete bikes with wheels removed) are boxed up and shipped, precisely because they help reinforce the frame.

If a wheel is going to be removed for any length of time, it is just good practice to put the thru axle back in - it keeps the thru axle from being lost, and helps protect the frame.