Strongly prefer evening, as I can’t stand going to bed dirty. However, if I plan to get up early (4:30) to use the treadmill, I’ll wait until morning.
Morning, the better the gird my loins for wrestling with the business world.
But here’s a couplet for you night-timers:
"Jump into the shower
Wash the world from my back
I’m gonna get you baby
That’s a natural fact
In the night time!"
Mornings to wake up and clean up for work. Nights to clean off the days funk, in hopes that the princess will want to snuggle. Scalding hot to soak dem old bones.
I shower after exercising, and/or in the evening right before bed.
And after I swim at the MLK Jr. Natatorium, I take a “rinse” shower to get that nasty chlorine feel/smell off me.
Night, before bedtime.
In the '70’s, here in the U.S., there was a sitcom called “Carter Country”. In one episode, the Sheriff and the Deputy had to share a living space for a time, and the question arose as to who would shower, and when.
The deputy chose to shower at night, to which the sherrif replied “You mean, you get right into your clothes in the morning after your pores have been open all night?!”
The sheriff chose to shower in the morning, to which the deputy replied “You mean, you go to bed with your daily dirt?”
That last quote changed me to a nighttime showerer, and I haven’t changed the habit since.
Night, before bedtime.
In the '70’s, here in the U.S., there was a sitcom called “Carter Country”. In one episode, the Sheriff and the Deputy had to share a living space for a time, and the question arose as to who would shower, and when.
The deputy chose to shower at night, to which the sherrif replied “You mean, you get right into your clothes in the morning after your pores have been open all night?!”
The sheriff chose to shower in the morning, to which the deputy replied “You mean, you go to bed with your daily dirt?”
That last quote changed me to a nighttime showerer, and I haven’t changed the habit since.
Morning. If I don’t shower in the morning, I never wake up.
Besides, I wake up every morning with a near-fatal case of Don King Hair. The only thing that can save me is gallons of water and vigorous shampooing.
However, I am more than happy to accompany my SO into the shower at any time, day or night. It’s just the kinda guy I am.
Night. If I put it off 'til morning, I am cranky. I like to wake up, put on clothes, brush teeth, and hit the road. Its
cold in the am, and cold & wet is not a good personality for me.
I’ve noticed that most of us with long hair tend to shower
at night and let it air dry.
Mornings. I have to steam my hair in order to get a comb through it.
I also shower at other times if needed, like after a session at the gym, or when I get covered with sawdust. That sort of thing.
Mornings for me, too. I just prefer it. It helps wake me up, and even though I hate getting up at the time I do for school, I kinda like the quiet. I commute to school (about 45mins drive), while my housemates just have to walk across the street, so I’m the first one up, and usually even by the time I leave, only my SO is out of bed. Besides, I hate showering at night, going to bed, and getting all sweaty. Ruins it, you know? 
Mornings, plus any other chance I get. I LOVE taking showers. I like brushing my teeth, too. I guess I’m pretty fond of the bathroom in general. I always shower at night if I’ve been out to a bar…don’t want my pillow to have that “bar” smell. & I shower before bed in the summer. I always have to shower in the morning, though, because my hair, if left to its own devices, is all crunkly and awful.
I don’t really like it when my BF showers before bed, though. Then he smells like soap instead of smelling like him. I just LOOOOOOOOOVE that slightly funky guy smell.