Our Swiss quartz movements are accurate to -10/+20 seconds per month.
Automatic movements are accurate to -10/+30 seconds per day. In our experience most perform better than that but if your watch isn't within these tolerances please drop us a line: service@elliotbrownwatches.com
If your automatic is running fast, it may have become magnetised from your tablet cover or another magnetic source like an iPhone Magsafe case or loudspeaker.  Our in house servicing team can de-magnetise movements quickly and easily.