Trying to get every available byte of available memory for programs to run was an art. I had multiple config.sys files that I'd use for different purposes. That's one of the uses of 'warm.com' for me. I had written a batch file that would (among other things) bring up a list of configs for specific purposes I'd select the one I wanted, and it would copy it into place then reboot.
I also had a really hairy AT command sequence I tweaked for a long time to get every bit of speed possible out of my modem. Thank God I don't need anything like that anymore.
Remember when you had to worry about filling up your hard drive? Ha, I don’t even think about it any more, and I do quite a bit of photoshop work.