@maxdancona,
Actually, there, their, and they're are homophone words. It is my opinion that the brain and your fingers type or hand write those words faster than you are actively thinking about them. Mostly you don't actively think about them. I have known how to use the words for decades but still goof up since when I type fast it sounds correct to my mental ears as I am rushing off to type the rest of a paragraph.
I have caught myself on ridiculous grammar mistakes sometime later and I make those for a similar reason, that probably back in childhood I had mixups on some grammar matters and and some early but incorrect form is showing up in fast typing. It's mildly embarrassing but I don't really care.
I agree with others that communication is what matters. If you are writing a science paper for publication, of course you want it letter perfect, aside from wanting the science to be well worked in the first place.
I've studied five languages, never - except for english - to the level of speaking them very well. I've always enjoy the grammar of those languages, despite not being a swifty at remembering all of it when I speak, or attempt to speak. I've greatly enjoyed whatever literature I've read using what I've learned. Never mind literature, I've enjoyed trying to read newspapers.
Saab, I think, knows several languages fairly well.