Traditionally people were told that they should treat their artificial eye as they would a new pair of dentures. Clean them every day and leave them in a glass of water overnight.
Maybe through a bit of laziness or self consciousness people left them in for longer periods of time. This resulted in getting a much more comfortable wear from the artificial eye. The reason for this is that there is an oily substance in tears that will coat the eye prosthesis. Once this coating is in place the body no longer recognises the prosthesis as a foreign body.
I recommend people remove their prosthesis fortnightly for cleaning. I am also comfortable if people leave the prosthesis for longer periods of time. The eye socket will usually tell you when the prosthesis is due for cleaning.
The people who remove the prosthesis daily can find changing their habit a bit of a challenge. Nobody likes change. People who do make the effort to leave the prosthesis in for longer periods of time tell us the increased level of comfort is incredible. They wish they had done it that way from the beginning.