An episode that ends around 10:45 pm tends to be followed by another one, which is roughly how a reasonable night becomes a short one. Seeing the exact time remaining, ticking down rather than sitting still, makes that decision a conscious one instead of something that just happens.
There is one number to read and nothing to choose: hours, minutes and seconds counting down together towards 10:45 pm. No start button, no options, no settings page to get right beforehand — just the current gap to that time, updating on its own for as long as you need it.
Twelve o'clock is where the 12-hour clock is at its weakest, since 12 am and 12 pm are read the wrong way round often enough to cause real trouble. Writing a time as 22:45 removes the problem outright, because a 24-hour figure only ever points at one moment in the day.
Common questions
What happens if 10:45 pm has already gone for today?
The count simply carries on towards the next occurrence, which is tomorrow. That rollover happens on its own — the page does not need reloading and there is nothing to reset by hand.
Which clock does it use?
Your own. It reads the local time and time zone from the device you are looking at, so the figure reflects where you actually are rather than a fixed zone written into the page.
Will this alert me when the time arrives?
No. It is a live number rather than an alarm — nothing rings, buzzes or notifies you at zero. If you need to be interrupted at 10:45 pm, set an alarm as well and treat this page as the running total.
Is it affected by the clocks changing?
Only in the sense that your device is. When the change between GMT and BST happens at the end of March and October, the device adjusts and the countdown follows it without anything to do here.