[ccarlisle]

Even if you bought the exact same batch of the same paint- or even had the old can of the original paint - paint degrades over time and changes colour. Rarely is a ceiling touch-up job effective and usually calls for a total repaint.

It is however a comparatively easy job. Long, yes; 'involved', yes...but the results are worth it given the alternatives. Like: 'live with it'...

 

[jsheridan]

The job is opened up now. Do you want to skip a two-three hour job now and regret it every time you look at it in the future, kicking yourself, asking yourself why I didn't paint it when I had the chance. Paint the ceiling, don't live with regret.

 

[Gatorb8]

I would repaint. Touching up ceilings can be touchy if you do not use the same product originally used or if the original product used was not a true flat. There are no true sheen police to monitor paint brands so sheen characteristics are different in each brand. As a rule of thumb, the higher the sheen the less likely the product will touch-up perfectly over time.

Most brands that score really well in consumer magazines carry a higher sheen to make them out perform competitors but the standard consumer does not investigate further nor do the big box facilities explain thoroughly.