Have had my scale for about 5ish years and it was off by .06g. (AWS LB-501)
then wouldnt that mean everything you weighed was also off by 0.6 equally meaning you just would of lost a little bit of ml?
Not exactly, though that could be the case. Reason though is scales can become calibrated differently when the amount of weight added is different (high end vs low end).
On an LB-501 its easier to tell because it comes with two 200g calibration weights and does a 2-pass calibration; I own one with well-kept weights (no scratches and always wiped down before use), and sometimes placing one weight reads 199.06 and placing the 2nd weight reads 400.03 (or similar). Basically both the mid-weight and the high-weight ranges became calibrated in different directions.
So its good to check your calibration every day that you use it. You dont have to recalibrate, just drop one weight after another and see if the scale reads 200g then 400g. If they're +/- .03g off thats acceptable tolerance still so you wont gain much by recalibrating (unless like in my example above they're off in different directions). Lots of things can mess with calibration like room temperature, warm-up time, unlevel surfaces, even EM interference.
Does the ads lb501 come with calibration weights? I just bought a scale on amazon (was mixing by volume before) and I can sometimes get 15 drops in before it even starts recognizing that I’ve added anything. It says I need a 500 g weight to calibrate it. I’d rather buy a new scale that comes with weights, than have to buy weight separately. I also didn’t want to have to spend 40 on a scale but I guess there’s a reason a huge chunk of the community uses the lb 501