What follows is a slight reworking of an email I just sent to a client. I think it’s broadly useful enough that it deserves to be shared publicly.

Here’s the scenario: The client’s family business operated for many years under her father’s name, but when he retired and she took over, she changed the name. In the several years since, she has built a strong reputation for the new identity, and she was wondering if it was finally time to let the old domain name lapse.

Short answer: No!

Here’s the longer answer, which also addresses the natural follow-up question: Why?

First, “google” your old domain name. Just go to Google, type the old domain name in the search bar, and see what comes up. You may be surprised how many websites out there still have links to URLs with your old domain.

Assuming you kept the old domain configured as an alias when you built your new website, if you keep the domain, those old links will still work, and redirect to the current site. If you were to let the domain lapse, those links would stop working. (Whether or not anyone is actually clicking those links is another matter, of course. If you have Google Analytics or other site stats, check your referrers for some insight on that.)

The same goes for email. Some people may still have old business cards, or for other reasons might still try sending email to those old addresses. If you have them configured to forward (which, again, you should have done when you initially made the switch), then you’ll still get those messages.

Another thing to keep in mind: if you let the old domain lapse, someone else will be able to register it, and could put it to nefarious use — phishing, scams, or just generally sleazy content. I have seen it happen. Even the best case scenario — no one registering it — will result in it loading a “this domain is available” placeholder page with the domain registrar, which may give people the impression you’ve gone out of business.

Given the relatively low annual cost of a domain registration, my recommendation is that you should keep your old domains registered for as long as you’re in business.