So... I have been in Pattaya for about 6 weeks. Before I left I bought CVS brand Deet repellant, quite a high amount of deet compared to other brands. I put it on during the day when I go out to places where I've been bitten before - the beach and the hill areas. In the past I was also bitten in my room at night a few times. This time I've changed rooms. I don't use a net to sleep under and anyway dengue mosquitoes bite during the day, so they say. A net would be a bit of a pain unless you have a bed you can hang it on.
I'm not sure if it's the repellant or maybe the dry weather, but I haven't been bitten once, day or night. I don't go out a lot during the day anyway cause it's just too hot, but I do walk / jog in the mornings in an area where I was bitten before. That was mainly when I went off the road to pee. The wooded areas around the roads are drier now too.
In the past I knew someone who lived and stayed in Pattaya and got dengue.