Generally speaking, NO. Typically, a local agent can provide you with what known as a CMA - comparative market analysis - with no obligations. This will help help you get a better understanding of what your home could be offered for in this current market. Make sure to get this CMA from at least 3 local agents so you can compare.
Real estate agents are here to help you make the best informed decisions. Make sure you let the agents know that you just want this info to understand what your home is worth as you are still doing your homework and are not yet ready for any commitment.
Ask your friends and neighbors for referrals for local agents and make sure to also check the selection of local agents in our Lexington, Ma member directory here:
Hope this helps!
Social Media Guru at Trulia