Quote:

My bailer (obviously mis-named) sees plenty of use early in the day as it is common for me to drink a litre or more of water before shoving off.

I think that's a very good point and sound advice.
If you look at many peoples liquid intake in the evening, you can see the potential for problems the next day if the conditions are right.
It's no secret that as we age ( especially men) we need to urinate more often, but in smaller amounts. Many campers both young and old, dread the midnight P-call, especially in the buggy season.
Consciously or not, people tend to restrict their fluid intake before bedtime.
We also might have some evening cocktails. Alcohol dehydrates you and even a few after dinner cups of coffee with or with or without booze in them adds to the dehydration, caffeine being a diuretic as well.
Even in winter we dehydrate overnight, even more so in warm weather.
It's very common to have your morning urine dark, a sure sign of dehydration. Then many of us have a cup or two of morning Joe, and we make a bad situation worse.
I always have at least a liter of water before/immediately leaving morning camp, even though I know the coffee I had will make me pee a lot at least until it's flushed from my body.
Medications can change urine color, so those who take them, might find the urine color test insufficient for their hydration assessment.
For the majority of us, peeing as clear as possible and consuming enough fluids to keep it that way 24/7 will go a long way in avoiding dehydration.
Still with the brutal heat and humidity were facing this year, there comes a time when you have to know when to get off the water and stay off it. Start at first light and quit by noon. If you need to travel more, you can always start again late in the day. This is where those built-in camp days come in handy ;)