For me it's a combination of just wanting to feel good about myself (or at least as good as I can) and working in an industry (Financial Services) where appearance is important. And maybe being brought up as a child to make an effort so dress well for church, Sun lunch etc, always polish your shoes, brush your hair etc.
I have PCOS so don't have the best skin so have looked after it religiously since my teens. I always take my make-up off before bed (I can probably count on one hand the number of times in my life when I haven't). I have always moisturised, eye cream, etc etc. I moisturise my whole body every day. I put oil on my cuticles before bed plus hand cream and foot cream. I always shape my nails, trim my cuticles and put Nail Envy on them so they look presentable. When I wear nail polish, I always remove it the instant it is chipped (I think chipped nail polish looks trashy).
My hair is fine and wavy and has a mind of its own. I wash it every morning in the shower without fail. A quick blast of the hairdryer and it's dry in 2 mins. I pumice my feet in the shower every few days. I also shave underarm every day and do my legs every few days. Although I'm fair and not hairy so it takes less than a minute. I almost always wear light make-up which means CC cream, a dusting of powder, natural lip pencil, maybe a natural shade across my eyelids and brush my eyebrows. If I have a tan and I'm off work, I may drop the CC cream. Obviously for work I will put on 'proper make-up' so lipstick, blusher, eye make-up. From waking up to leaving, I'm usually ready in 45-50 mins although some of that is faffing (I'm not a morning person). It may be slightly longer if I have to faff around with tights, finding the right jewellery/shoes etc. I always add a splash of perfume before I leave home, even if I'm just going to the gym.
I make an effort with how I dress. I try to find clothes which are comfy but stylish, maybe a little edgy. You'll never find me in Joules or Boden put it that way.
I find spending just a few extra mins a day on maintenance saves time in the long run. And now I'm almost 50, people tell me I look younger so I think the effort pays off. A friend says that I always look very glam but she doesn't see me in the gym every day with my hair scraped off my face and sweat running down me.
I think what I've written sounds quite vain and I'm really not vain at all. I just don't think I have the best base to start with (due to years of paranoia about my skin) so I have to put a little effort in to look ok. My old personal trainer once said to me "you just don't care how you look at all" but that's because I'm all business in the gym (I'm there to work and sweat rather than take selfies and look pretty) and because he lives in TOWIE land. 