Solved Make sure that you lubricate your hotend.

As I was using a lot of PLA to print various things, I've noticed that the print layers started to show gaps. I didn't think that it was an issue until filament started to intermittently bind in the hotend. Sometimes it was so bad that it would air print in the middle of a long print, and I had to start the print from the beginning. I gave the filament a shot of WD-40, and it started to print very well again without any adhesion issues or gaps between layers. I saw some oilers on Thingiverse which run PLA through an oily cotton ball but haven't tried that. Another time I've used wire pulling lubricant which worked for a very long time. I'll see how long the WD-40 lubricant lasts since it's very thin, and will probably evaporate faster than a thicker lubricant. One person suggested using cotton seed oil in the cotton ball.