Yes, you really do need a Tenant Rep
A tenant rep is an real estate broker who represents a tenant in a lease renewal and/or alternatives to new locations in the market place. Why do you need a tenant rep to renew your lease? Because yo have been in that lease for the last three years and the market has changed, the inventory has changed, the pricing and terms in the market have changed, and only a commercial real estate professional is going to be able to have a handle on those changes and be able to aid you in getting the best possible outcome to the renewal or new space question.
The best part is that in 99% or the circumstances, the tenant rep will be compensation by the landlord/broker of the final space you occupy. Who doesn't like free consultations?