You have already made the transition into retirement. Congratulations.
With any luck, the years post-retirement are ones of relative calm and little change in your financial life.
You've got a lifestyle, you know what your big ticket items are, your insurance coverage and estate documents are in order, your tax situation changes very little from year to year, you've adjusted to spending down instead of saving money in short, your financial life is smooth sailing. Until a bear market hits. Or a serious illness. At that point, it's incredibly helpful to have an advisor who's right there and who knows you.
As you get older, you'll likely have new financial concerns. Funding college for grandkids. Simplifying your financial life. Bringing adult children in on your finances. Planning for how and where you'll live as you age. Even if you were a do-it-yourselfer early in retirement, you may find that later in life you're eager to have a sounding board, and delegate the responsibility for investment management to an advisor.