What's the best way to use my dehumidifier?

[2anddone]

My house gets condensation on the inside of the bedroom windows pretty much continuously from November to March.
I clear the windows each morning with the window vac to try and stay on top of it and last winter I also used the Poundland dehumidifier boxes of crystals in each room which seemed to work ok (but not fantastically)
I have bought a portable dehumidifier which has arrived today (I couldn't get one last year as was out of stock!)
When is the best time for me to start using it? Do I use it now or wait til the condensation starts? Do I then run it 24/7 (it has a timer) or only at certain times of the day/night?
Sorry for the really boring questions!!

I've got a Meaco and I just leave it on 24/7 emptying when it gets full. During winter I usually empty twice, during the day and before bedtime

@BetsyBobbins thanks for answering do you leave it on at this time of year too?

I use mine all year round, although not nearly as much in Summer.

No point using it when you have your windows open or you’ll be dehumidifying the world. Also, the air it spits out is a slightly higher temp than what it takes in so bear that in mind on warm days.

On what would be a regular summer - hot and dry days - not during the day, only at night after closing the windows. But this has been one the wettest and coldest summers we've had so I'm leaving it on pretty much all the time. It does use quite a lot of energy though.

It's also worth mentioning that I live in a tiny two bed flat né my bathroom has no windows, so there's a lot more room for humidity and therefore condensation

how much does that cost to run if it's left on 24/7?
DS uses his dehumidifier to dry clothes, but only for short spells, maybe an hour at a time.

Thank you my windows are open constantly at the moment but I will start to run it after showers etc and once the windows aren't open for as long

Our windows are open during the day even if it's raining. Winter, I try to open windows for an hour or until I can't stand it any more when it's dry enough. Last year, we were drying washing on an airer, rather than using tumble dryer, so needed to run our old dehumidifier. I bought some cheap temp/humidity displays and aimed to keep humidity under 60%. Managed that putting dehumidifier on for two hour blasts (using smart plug and timer on app) 3-4 times a day.

My daughter noticed damp on her ceilings and bought a dehumidifier that registered humidity level and needed to run it constantly for over a week to get down below 60%.

We also have trickle extractor fans in bathroom and cellar that run 24/7 but kick in on higher power after baths and showers. They have been much more effective than the dehumidifier.

When it's not the heating season I don't run mine unless there's some laundry which needs drying urgently on a rainy day, eg quilt, or I'm trying to dry something specific like a shampooed carpet or a flood from a leaky pipe.

But once I'm paying to heat the air, I don't open windows very often except the bathroom after a shower. Then I put the dehumidifier on for much of the day, and it just flicks itself one and off as it needs. Like PP, I aim for 60% Relative Humidity (or sometimes 50% if there seems to be a lot of difference in humidity across the flat, according to my little humidity meters).

And yes, if you've had damp accumulating in the fabric of the building for a while, it will take a similar while for it to dry out. One place I lived took months to get down to a regular reading of 60%.

I run my 24/7 but move it around the house to a different room each day. Probably a bit obsessive but I live in a Georgian house so old and needs it.