My strategy is make small functions that do one thing then combine this small functions to create larger ones. When a new requirement is added to change the lar

My strategy is make small functions that do one thing then combine this small functions to create larger ones. When a new requirement is added to change the large functions you probably have to change just one or a few of the small functions but many of the smaller functions are unchanged. Also when this new requirements are added you can reuse the smaller functions, most issues I had to fix is understanding code that evolved over time and ended up to be a giant function that does too many things , with many branches. Also make the code easy to read and understand, have good naming convention for the small functions and variables, add comments if you have to do something unusual (like workarounds for weird quirks or bugs) so it makes sense 3 months later when you read the code again and you forgot most of it.