The time of day you wash affects your skin, hair and sleep. Apparently.
Do you shower as soon as you wake up, or just before nodding off to sleep?
Whatever your preference, chances are you have strong opinions as to which one is the superior choice.
While everyone has their rituals and traditions, what actually are the benefits of AM versus PM? We spoke to the experts to find out how the time of day you wash can affect everything from your hair and skin to your sleep.
Why you should shower in the morning...
From a purely mental point of view, many of us far prefer showering in the morning. It definitely has the power to jolt you awake and press the reset button for the day ahead.
Senior stylist at KH Hair Helen Stilwell thinks there are many benefits for washing your hair bright and early. She says: "If you wash your hair before bed, you still have the danger of it going oily through the night. This could be due to sweating, or your scalp producing too much oil through the night.
"If you wash your hair in the morning, you can wash away any oils produced from the night's sleep and it will feel nice, clean and be easy to style. It might take more time than washing your hair before bed, but it has a feel-good factor when you do it in the morning."
Studies show that showering in the morning does actually set you up for the day. If you turn the water cold for the last few minutes of your wash, your metabolic rate will increase and your body will effectively be shocked into action. It might not sound like the most pleasant start to the day, but it could make you more alert and reduce fatigue.
Why you should shower in the evening...
Many of the skin experts we spoke to agreed that showering in the evening was the best course of action.
Dr Anton Alexandroff, consultant dermatologist at BMI The Manor Hospital in Bedford, says: "During the daytime people sweat, and sweat irritates the skin so it is helpful to wash it off and moisturise your skin after showering."
Dr Ekaterina Burova, consultant dermatologist at BMI The Saxon Clinic in Milton Keynes and BMI The Manor Hospital in Bedford, agrees and says: "From the skin health point of view, it is better to shower at night, not only because skin will be cleansed from the sweat and dirt acquired during the day, but also because, according to research, intense exercise reduces skin immunity and therefore raises the risk of skin infection."
Celebrity hairdresser, Mark Woolley from Electric Hair says: "Although both are perfectly fine to do and it's very much down to your own time and needs; it's perhaps preferable to wash your hair in the night so that you can allow it to air dry and not always go for the heat of a hairdryer.
"You're also washing out all the dirt and grime from the day and it means your bed and pillows are kept clean. There's always the worry of extreme bedhead the next day, but, as long as you ensure your hair is fully dry before you go to bed, your hair will be fine!"
Actually, you should shower twice a day...
It makes sense that many dermatologists recommend showering in the evening - after all, you need to wipe away all the grime that builds up over the day.
However, facialist Jasmina Vico has an alternate suggestion, and it's pretty compelling. Vico firmly believes in taking two showers a day.
She's pro the evening slot for many of the same reasons the other experts give. "After a long working day, we should enter our beds with a clean face and body," she says. "It's especially important for those living in cities, as our skin absorbs pollution, which means sleeping in dirt and grime if we don't wash."
But she adds to this: "I firmly believe we should still shower in the morning, as bacteria and sebum production increase overnight and the skin needs to be cleansed."
This is practical information for your skin, but she also thinks it helps your mental state going into the day: "A morning shower will freshen and awaken the senses - it gives you time to cleanse your aura, mind and body before the day starts. In turn, this will help reduce stress levels during a busy work schedule."
Consultant psychiatrist and sleep specialist at BMI The Albyn Hospital in Aberdeen Dr Olga Runciee thinks that there are benefits in both the morning and evening showers when it comes to your sleep.
Runcie says: "In order to get to sleep better, our bodies usually drop temperature by almost one degree. So, if we have a hot shower in the evening, the body starts cooling. This reduction in temperature naturally creates sleepy feelings and might help us to fall asleep."
Whilst a warm shower might help you fall asleep, the logic also works the other way around. Runcie adds: "A cool shower in the morning might have a stimulating effect, and can help us to wake up."
If you really wanted to be a naysayer, you could argue that you shouldn't in fact shower even once a day. There is an argument that the hot water strips the skin of its moisture and can damage or destroy microbes that are key for good health.
At the end of the day, most of the experts agreed that there's not a huge difference in when you decide to shower. It's about knowing the pros and cons, finding what's right for you - and not forgetting to put on deodorant afterwards.