My HF digital caliper has worked well for me. I also bought the plastic model for $1, which is good enough if you only need to measure within a mm.

I haven't had to replace the battery in the 5 years I've owned it. Other than turn it off when I'm finished I take no precautions.

In a previous version of someone's post he wrote that batteries were so expensive he threw his away when the battery ran out. I found a supplier, azbatteryman, on eBay, who sells them for about $1.65 for 10, ship from the US. I bought some even cheaper from China but they were all no good. Considering postage was $0.65 he must be getting them for a penny.