If your company needs a new office space then you need to take the steps to acquire it. If you have a lease renewal coming up, you should do some homework to understand what the fair market rent should be.
Here are some decent free resources for Seattle companies:
None of these will provide enough information to understand what the complete lease package will be until you physically tour and request a proposal from the building.
Any company that is either growing fast or has more than 10 employees should then hire a Tenant Representation Specialist to help find their next space. Here are a few reasons why I think hiring a Tenant Representation Specialist is worth it. Additionally, when I search for space for my customers I use the three major subscription based services: CoStar, OfficeSpace, and CBA. Here is more detail on the process of finding office space.