I agree. My kitty had an eye infection when she was a kitten, red eye (or the eyelids were red rather), she was squinting and there was the mucous. That was 4 yrs ago or so, so when she got like that again (mainly the red eyelids and the squinting) I figured that's what she had again. Wrong.
I did ring the vet since it didn't go away on its own after a day and a half, and they said to bring her right in- they do not recommend just waiting for a few days, since you don't want to risk anything to do with the eyes. Turned out she had a small wound in the eye (don't know the terms here), not an infection at all, and although she got eye drops, it would have been totally different if she had had an infection and had I just treated her for one, could have caused damage. As it is, her eye got better really fast, and though she got the problem again a few weeks later (the vets couldn't figure it out- another wound, in the other eye, and they didn't look like they could have been from my other cat's claws or anything) and had to go in a second time, this time I got the check-up for free, courtesy of the vet.
Even though with some problems I may try to treat them at home, or wait and see for a while, eye problems are not one, since the eye is a very sensitive organ and I would not want to risk causing permanent damage there.