Quoted from Black_Knight:
Just put batteries in and replace them once a year. If you are in the hobby you'll be in your machines frequently enough.
The batteries die and you lose your settings long before they start corroding.
Tell that to my TZ board! I install brand new Costco-brand batteries every Christmas, but 6 Months later and they already leaked all over the battery holder. From now on I'm going NVRAM or Lithium in everything. Now it's going to cost more to fix the board than years of batteries ever would have...