Umm, I can't help you with any but the contacts.... Definitely change them in the time instructed. If you wait to long you are definitely increasing the chance of an infection. It's not too bad if you leave them in for maybe a week after you are due for a change, but definitely don't wait too long. A few things could happen if you keep them in too long: 1. Infection 2. Dirty, blurry contacts that can lead to an infection 3. Protein buildup that results in pain that stings like a mother when you take out/change your contacts.....(if pain doesn't do away within an hour or so then you most likely have an infection) Trust me, all this has happened to me....had a pair in for about 11 months.....don't ask why, because I really haven't the slightest idea why I did not change them. Write down the date that you change them and aim for that same date the next month. It makes things a lot easier.