The Fitbit Aria scales (older model FB201B) seem to have a design flaw which causes the plastic part in the two front feet to stress fail after a relatively small number of uses (typically just after the warranty expires). Once broken, the scale doesn't detect a zero load causing the display to loop between 'step off' and 'sensing' leading to battery drain. There are no replacement parts, rendering a $120 scale useless for the sake of a 0.10c piece of plastic. It is relatively easy to open (see comments for video) and fit this part which corrects that flaw.
Don't know if this part will withstand the test of time any better than the original as of yet. will update anon.
After 9 months of flawless operation the PLA part looks like its starting to fail (might want to print a few of these). I hope to try different materials next.
Must print with supports. Slic3r gave a good result. Mine printed in PLA, ABS should be fine but does brittle over time.
Gently pry off support and clean flashing