Mold control: Dehumidifier vs Ventilation

Something I've never quite had a grasp on.

When I moved in to my flat, my landlady said to keep a window open constantly and run the dehumidifier once a week.

I've never bothered to run the dehumidifier because it seemed crazy waste the electricity running for a day when I was just going to re-open the windows to allow moisture back in?

I've kept my windows cracked except on the coldest of days/nights (I enjoy the fresh air and have a very economical heating system).  I don't have tremendous mold problems at all, but often feel like I'm having allergic reactions (itchy eyes, runny nose). 

Anyone care to clarify what I'm really supposed to be doing to manage mold?

Mold. Hate it. Was the bane of my existance for a year.

You can also see its a well discussed topic here on UKY  
http://talk.uk-yankee.com/index.php?topic=33764.0
http://talk.uk-yankee.com/index.php?topic=41123.0
http://talk.uk-yankee.com/index.php?topic=218.0
http://talk.uk-yankee.com/index.php?topic=53146.0
http://talk.uk-yankee.com/index.php?topic=49404.0
http://talk.uk-yankee.com/index.php?topic=49437.0
http://talk.uk-yankee.com/index.php?topic=9178.0
http://talk.uk-yankee.com/index.php?topic=57383.0

Personally, I never had any luck with any method of prevention and resorted to making myself ill by using lots of bleach/mould killer after it occured.  
Good luck!!!

Thanks PB, that totally helped!  I had browsed the old threads but not entirely.   

I think I have my answer:

Ventilation is for the summer (when you can have windows open), dehumidifiers are for the colder months (when damp is worse and it's too cold to have windows open).

And it WOULD be a mistake to run a dehumidifier and then open my windows or the rest of the week.  Do one or the other.

Now I'm off to peek in all my corners armed with bleach.   

Ventilation is for the summer (when you can have windows open), dehumidifiers are for the colder months (when damp is worse and it's too cold to have windows open).

And it WOULD be a mistake to run a dehumidifier and then open my windows or the rest of the week.  Do one or the other.

That sounds like a perfect answer!    Good luck!!!