Thought it would be useful to mention that I would be far behind my current state if not for a comparison tool. Mainly I compare versions of my own algorithms, also sometimes those in forum posts on Quantopian that are closely related to see what changes someone made.
Of course, on Linux/OSX, diff is quick and there's even a diff.exe version (of all of those command line tools) for Windows. Then there's git et al. For me, the best productivity happens in GUI programs/applications. Changes from one file to another can also easily be made. One program called Compare It could be the front-runner because there's a list of Alternatives to Compare It.
I use Compare It and there is one particular thing about it that has helped a lot that I'll mention. First here's a screenshot from them. I don't make any money promoting this, I just feel bad for those being slowed down by not having caught on to how great these can be.
Screenshot from the web ...
The tip: Instead of browsing for each file on the drive, on opening the program, I open two dummy text files, 1.txt and 2.txt, then copy and paste the code from two algorithms (from backtester and/or Notepad++) over that content. That's ctrl-a, ctrl-v. Then ctrl-s to save. Then F5 to refresh. Mostly keyboard and fast.
Also its options are many, and I've made some changes that were a big help, and except for colors (highlighting) I forget what they were, maybe having to do with multiple spaces for one.
A comparison tool can greatly increase productivity, efficiency in developing algorithms.
How about yourselves?