I carry a multi-tool all the time just in case. In general I don’t even need to pull the tire to change a flat thanks to my Brompton experience. I have a great tip for all of you. This will work for all bikes usually too, not just internal hubs.
Go in the kitchen, get the beverage of your choice. This will take a while to do the first time. Before starting make sure you have all the appropriate tools to remove the rear wheel of any bike you are going to do this to. Make sure you have 1 (or more) spare tubes of the appropriate size for your bike.
Remove the rear wheel. On the side opposite the chain, slide your new tube(s) over the swingarm of the bike. Keep the center of the arm in the center of the tube. What you are looking for is the tube to ultimately have the axle pass through the middle of it. Move the tube up the frame until it is safely out of the way. Zip tie it or use some other method to secure it. Next time you get a flat, lay they bike on its side. Peel one side of the tire off the rim, move old tube out of the way. Move new tube in and close tire up. Use ties to secure out of the way if you plan on re-using or you can cut the tire off.
I leave the old tube in place and then use my tire repair kit to fix it when it is more convenient. By don’t think I have never had to pull the rear tire now except when I want to. On one bike I keep a spare tire folded up as well along with the tube.
I can change a flat in under a minute. This tip will work with derailleurs too. Try it and you’ll be amazed how simple it is and it sure helps when I am commuting to work. Now I can change the tire at home instead of in the rain or heat. Some odd reason since doing this I rarely get flats. ;-)