I always thought that people who said it was dangerous to wear contacts that were not fitted for you were stupid overcautious know it all's. WRONG! They are RIGHT.
Shops sell all sorts of contacts where I live that are samples. From every brand you have ever heard of- and they are GREAT quality, never tear, authentic contact lenses. I was not a frequent lens wearer, either. I would only wear them went I went out to a club or a bar, which was MAX 2 times a week. I had no trouble inserting them, touching my eye does not bother me. I always had allergies in my eyes, so I was used to my fingers being in my eye. :) But I could even put them in without a mirror. There was NO indication that there was ever going to be ANY problems.
What I did not know was that even though they did not feel scratchy or even irritating, they were causing long term damage. I have recurrent giant papillary conjunctivitis due to the wrong size contacts. At the time I discontinued wearing the lenses, I had developed a very deep corneal ulcer due to erosion to the corneal epithelium from the contacts moving the TINIEST amount when I blinked - I did not even feel it when it was happeneing. Days after they came out, it felt a little scratchy, and the visit to the eye doc was after I had "allergies and scratchy eyes" for three days. Nope, not allergies. It was the contacts I had worn four days before.
To this day my vision is still affected. I NEVER thought that - AT MAXIMUM - 5 hours a night for two nights a week would do this. I got fitted for contacts and never had the problem again. Due to the scarring from the ulcer, though, I really cannot wear lenses any more. (more fear on my part than doctors orders) I have very deep brown eyes with little to no depth, and I HATE them, but not enough to go blind over.
Spend the $90 and get fitted. The drops for giant papillary conjunctivitis are $220. The drops for the bacterial infection are $75 and the steroid drops are $140. The eye doc visit was $90 and the sample lenses were $19. I could have spent $90 for a contact fitting exam instead and $30 on 6 pair of lenses and never had to go through that mess. $120 sounds a lot better than $500 , eh? :)