Obviously, digital color samples and formulae as those produced on this site are immune to ageing. However, as mentioned elsewhere, should you need an exact color match for a real-life finishing, matching against a physical sample is an absolute requirement.
Physical samples provide much more reliable means of visual matching, but an intrinsic property of all physical color chips is that the shades may change with time. Moreover, the effect of ageing is usually not consistent across the range of colors: some colors will change more than others.
Color change can be minimized by observing the following procedures.