Is this a good idea to share a service tag for a Dell laptop?

I can't see any reason not to provide the service tag. It only provides specs on the build.



The express service code beneath it can sometimes be used to reveal the original purchaser of the machine. Even that isn't critical info but it is a little more along the lines of personal information.

I would be more concerned about completely wiping the drive with a three pass overwrite BEFORE reselling any laptop or tower. It's easy enough to download & install a clean ISO for whatever operating system the machine is using. (You can use the service tag on a Dell to obtain any missing drivers that are specific to the machine. )