YES. Even if you are healthy and you do not take any drugs you should sign up for part d coverage when you first become eligible for Medicare. If not, you will have to pay a late enrollment penalty.

If you have coverage from an employer with 20+ employees you do not need to sign up for part b right away. You may want to compare the costs and coverage of your plan vs a Medicare plan though. If you are on an employer plan with less than 20 employees you still need to sign up for part B when you become eligible.

Insurance agents are paid directly by the carrier. You do not pay any additional premium for going through an agent as opposed to going directly through the carrier.