I know there are so many variables. For a 21 year old living at home it's probably a very good salary!
For a single parent who owns a home maybe not.
For me, I'm 35 and I don't feel this is a good salary for me. I'm in the Civil Service, I have a degree and master's, it's my own fault for possibly doing qualifications that haven't led to anything higher paid/more specific.
I'm an EO/Executive Officer grade which is junior. There are not many HEO/Higher Officer grades that don't require very niche experience or line management, there are also few fewer HEOs than AOs or EOs so competition is tough.
I'm looking outwards at the local council, third sector and private sector. I know money isn't everything but when you have things to pay for and any chance of saving then it does help. I think I'd feel comfortable on closer to 40k, whether this will happen is another matter.
Of course there will be people on under 30k who manage perfectly fine, it's all relative. Just wondered what anyone thought!