I used a fee-only financial planner for a one-time comprehensive review. Here's what it cost and what I got.

Cost: $1,800 for a full financial plan covering retirement projections, tax optimization, insurance review, and estate planning recommendations.

What I learned that I wouldn't have figured out on my own: (1) I was over-insured on my life insurance and under-insured on disability, (2) my 401k had a plan-within-plan option that allowed after-tax contributions for the mega backdoor Roth, which I hadn't known about, and (3) my asset location was suboptimal — I was holding bonds in my Roth (wasting the tax-free growth) and index funds in my taxable account in a way that created unnecessary dividend drag.

Return on the $1,800: I estimate the mega backdoor Roth optimization alone will be worth $50,000+ over 15 years. The disability insurance fix was pure risk mitigation that I can't put a dollar value on but am grateful for.

Conclusion: a one-time fee-only advisor review is worth considering if you have a reasonably complex situation. Ongoing AUM-based advising is usually not.