As a designer, you tend to be involved with many logos over time, both your own and others. Everyone and their sister’s lesbian roommate’s cousin has a logo, and you will eventually probably use them in some project. And if you have any sense at all, you back up all the art from your projects anyway. But I recommend keeping a logo archive, preferably in a convenient location for immediate use. Logos, when done right, are very small files, so they won’t take up much space. Not a week goes by that I don’t go back to my archive to pull up a logo. If it would otherwise take 5 minutes to dig up the right file, that’s a savings of over 4 hours, over the course of a year. But most importantly, it will inevitably improve the quality of your work. It never ceases to amaze me how many companies — large or small — can’t provide you good copies of their logos. By saving the best copy you can find of everyone’s logo, your work improves and you exceed your client’s expectations.
Please keep in mind that this post is more than 3 years old. Opinions change. Tastes change. Everything changes. I may still agree with this, or like this, or I may not. But everything is kept up here for archival purposes.