I just did! My pack has side pockets/pouches and I consistently use one for my first aid kit and water filter, so I sewed a first aid cross patch to it. This way myself or anyone in my group could instantly know which pouch contains the first aid kit! The other side pocket has a "poop" emoji! It holds the...you guessed it, toilet paper! I thought it would be fun to add the "other" emergency symbol! That's probably the extent of my patches, however, my son has been collecting patches from the various parks that we've hiked or camped. When he eventually gets a pack that he won't outgrow he'd like to put all these patches on it. He must have 10 patches! I rarely see patches anymore but maybe some day that practice will make a come back into fashion! Who likes and has patches, and who doesn't?