it's very important. but the motivations behind it are much more important.
for instance....dressing well, keeping in shape, etc are usually signs of self respect. When you let yourself go, you don't respect yourself much. Those are things you do for YOU
if you're comfortable with being overweight, you obviously don't respect your body.
If you're comfortable, with woring the same outfit from 1992 and don't want to change your hair you lack the very essence of life, which is change.
IMHO that's extremely unattractive and a simple minded mindset.
whole purpose of life is to improve yourself as much as possible. mentally, physically and emotionally
that doesn't mean that everybody who's big on taking care of themselves is not motivated by social approval (which is why i mentioned motivation is a huge aspect)...but chances are if they don't care about themselves, they won't respect themselves enough.
Someone who ONLY takes of themselves and is concerned only with vanity and lacks any internal qualities is a waste of time and has no substance.
you need a mixture both