I am going to paint our hall, stairs and landing below the dado rail to freshen things up as it's got pretty grubby. Decided to go for a lighter colour but one which still needs to tone with Crown Wheatgress above the dado, which is spotless and still looks good.
I bought four testers in B&Q as I just got hacked off with the way things were organised and couldn't easily compare things - I only want to do one coat btw.
One colour went on the same as the existing paint, but dried very much lighter. One, Dulux Crispy Crumble, looks positively grey on the wall, but looked like a very light, creamy brown in photos I've seen. Another is not different enough from the Wheatgrass. The final one has dried to almost the same colour as the current colour.
A worthwhile exercise as far as I'm concerned as I've previously made an expensive mistake based on a colour chart, not to mention the time it took to put right. But I do think they are overpriced.