My old scales had been acting up lately, I would get on and off it and every time a new weight would come up (Anywhere within a 5lb difference).

Fed up I bought a new scale... And this one is doing the same thing. I've tried weighing myself upstairs and downstairs, thinking maybe the floorboards were throwing it off as the house is pretty old.
This morning I tried weighing myself in the porch (To avoid said floorboards) and every time it came back with the same number.
The weight seemed accurate but I'm not entirely trusting the scale right now, as I would of thought I should be heavier, had a few pretty bad weeks over X-mas and not much running due to all the snow.

I imagine the scales probably right, just a bit frustrated and wanted to vent it Perhaps someone else has had a similar problem?

Meh, I ignore scale fluctuations or just average out several if I really want to. It's just too much trouble to get caught up in an exact number that is so influenced by "non-fat" (i.e. water, waste).

One day last week my scale weight jumped UP 5 lbs from morning to morning (same time of day, same clothes) even though I have been steadily losing 3-4 lbs a week. I didn't really gain 5 lbs, it's just that the previous weiging I was probably really low on water and the current one I was maybe a little high or something.

I personally weigh every day because I think the trend is interesting, but think it's impossible to micro-manage your scale weight day to day so why bother trying?

In an ideal world I think we all want to see a nice even 0.4 (or whatever) loss every single day we do the right things, but that is a pipe dream