Q: Should my LinkedIn profile be as extensive as my resume?
A: Generally, no. Of course, enter your current role and then select the most pertinent, meaningful prior jobs and schools. It’s not necessary to include each and every/short-term job(s), nor are all the details from a resume needed (e.g., clerkships during law school that are no longer relevant to what you do/want to do).
And yes, lawyers should have a LinkedIn profile: connect with others on and offline, and use the platform in searching for a job, in hiring, in developing business, and in making and maintaining your professional name and network. Do include a picture, do highlight key projects, do join relevant groups, do read and share information, and do keep your profile updated.