9 times out of 10 somebody else's code points the way. The tenth time, you didn't look hard enough. The exception to this rule lies in a very small % of coders who know who they are.
I hasten to add, I am not in that minority!
I hasten to add, I am not in that minority!
Now that I’m cognizant of this I first thoroughly review other implementations to try and understand why decisions were made, ultimately saving me from repeating the same mistakes.
Inconsistent documentation is also a problem.