We rent out a flat and wish to be able to touch up the walls between tenants. I have used paint from the same tin to do the touch-ups but it is lighter then the paint that has been on the walls for 3 years. (The paint in the tin still looked OK after that time and had not gone off.)
So what paint system can I use the next time I decorate so the paint will be easy to touch up without showing?
(We are in the UK if it makes a difference)