NOTE: This is a very general post. I am not too code savvy with back-end MAC structure, well…just enough to make me DANGEROUS!! (I have not broken any MAC I was not later able to revive…)
FROM ARTICLE: You may have heard that Apple plans to stop support for 32-bit apps across iOS and macOS. While iOS 11 will remove them this fall, macOS will continue to support them until 2019. Nevertheless, it doesn’t hurt to start early and find the 32-bit Mac apps. Read on to learn how to see which apps on your Mac are still 32-bit.
I bit that bullet, and updated my mac to Mojave. AllI have noticed is that it spins more! That impossibly because some of the apps are 32-bit*. The lates mojave OS update works better with 64-bit apps, to the point that you sometimes might need to update / upgrade for the app to work at its best, and you will get a notice on your screen when the app gets opened for the first time letting you know that an update or change might be called for.
So how do you easily determine which apps are 32-bit, or 64-bit? I did not discover this myself, but found this post which I am reposting here.
* it likes was also because I had 1/8 free space only hard drive, AND I needed more RAM.