I would suggest using a check weight and weighing it ten times in succession to see it it holds its value each time. Some digitals aren't worth what was paid for them in terms of repeatability.

I did a pretty good bit of shopping before I bought my new scale. I settled on a 1 mg scale (.015 gr) due to price and size. I use M3 weight standards to check accuracy and repeatability and also used them on my Ohaus 505. It's approaching 40 years old and still produces good accuracy within its limitations.

Don't use your fingers on your check weights. Cotton gloves or tweezers are the only accepted methods, if you want the weight to continue to be accurate. Keep the weights in a covered container to keep dust and debris off of them. Remember, digital scales round off their results, so you aren't necessarily getting the real weight.

This is the scale I use and I keep it out of drafts and on an anti-vibration pad, but insect spray used on red wasps is rough on the dust cover.