I have several bits of code that I take from gig to gig and reuse. I wrote a general data access layer a few years ago and have used it numerous times. It's saved me untold hours of time. Over time, we craft these indispensable little gems that we can plug into our applications over and over again. I'm definitely a fan of getting to the finish line as quickly as possible and keeping an organized collection of reusable code snippets helps to accomplish that. I, personally, prefer to keep these pieces of code in a code repository on a server at home. I have my repository set up so that I can access it from anywhere across the internet and when an opportunity to use one of these snippets arises, I pull it down and put it to the task. As far as organization, I find that arranging the code by Layer and then by purpose is sufficient.
I recently read a book on building wealth in which the author indicated that the amount of money you're making is not the important thing when building wealth. The acquisition of assets that generate income...and keep on giving...was the key. No matter how many lines of code you can write in a day, code assets will save you time and make you more productive.