I read once that you should be saving the percentage equivalent to your age when you take out the pension
Half your age actually, so if you're 40, it's 20%.
That's assuming you are starting from scratch at whatever age. So, if you start at 22, it's 11%. If you get payrises, as it's a %, it goes up with pay rises, but I've always suggested to people they try to add 1% every year or so anyway.
I am 50 and currently pay 50%, and am not starting from scratch, luckily I have a fairly high salary and v low outgoings (no mortgage or rent) but even with that and the base position, I am not looking at having a massive pension.
I do it to avoid the 40% tax band, might as well minimise tax now and benefit from that when I draw the pension as I'm very unlikely to be in any higher rate bands that exist then. Plus I can take the 25% tax free lump sum in five years.
But, anyway, lots of people do not have good or even any pension provision.