I have several Digital gauges and the batteries last a long time. They have three Volt Li-ion coil sized batteries. I cannot recall the exact size at this moment, but perhaps CR2032? These batteries have about a 10 year shelf live and even last a long time a standby current drain. Where as, the small button alkaline batteries that you find in many of the cheaper gauges do not last all that long. But like you said very cheap.and they eat batteries like no tomorrow
Some of the stuff you get from HF is ok and some of it is junk. If you really want to go that route, read lots of the reviews, especially the ones where people really try to study them and their performace. .Also on harbor freight I noticed this one micrometer kit . Is it usable or it’s junk?
I have some good mechanical gauges (Starrett, Mitutoyo, etc.) , but find I usually use my digital ones. For me the accuracy and repeatability has more to do with my measurement technique than the measurement performance of the gauge. My digital gauges typically have a 1 inch range and 0.0001" resolution. They switch from metric to inch scale at the push of a button ... a Nice feature. Also, while they say 0-25mm they range to a little more than 1 inch (25.4mm).
Dial gauge (plunge style) micrometer at ~$64 on Amazon. I mentioned it before, bit I check the resolution/calibration on these using somevery expensive 1 micron mechanical micrometers and the digital one is dead on and has less backlash. I find it really handy to have the long through plunger. Also, a known thead size for the tip.
--- Clockwise Tools DITR-0105 ( I have 3 of this model and the optional cable(s)) and the
--- Clockwise Tools DITR-0105N (which does not have the auto off feature for the display)
Even with the out the auto off feature the current value remains in the gauge and is visible when you hit the on button.
These particular units have a thicker and stronger metal case than the ones that cost about 1/2 this much.
C-shaped Outside micrometers that I purchased (set of 4 sizes, 25, 50, 75 and 100mm, $184 in 2021). Likewise, with 3V li-ion coin style batteries that seem to last a long time. They have both mechanical and digital read outs! I purchased these a couple of years ago and the batteries are still working.
Unfortunately, they are not selling this set any more, but do sell the individual micrometers.
Mostly, I use the smaller two sizes. If the price seems too good to be true, like $20, don't buy it. There are a bunch of knockoffs. There are versions with plastic handles which then do not have the mechanical readout. I have never tried those.
PS. I have purchased alot of parts from AliExpress and have never had a problem. Shipping is sometimes free and it can take up to 3-4 weeks to get the item as it seems the shipping carriers group shipments to the states and then fly them here. I did buy some cables that that turned out to be a different connector style(angle) than I ordered. I wrote the seller and he shipped the correct ones and said I should keep the others.