We’ve got a guy (apologies for using the word “guy.” I’m sure there are plenty of capable gals.) We pay him a flat 1% of the funds he controls. For us, that 1% is worth us not having to be “the experts” about our money.
When I retire in 3 years, I’ll have my IRA to either keep where it is, convert it myself, or give it to him or someone else. Not sure which we’ll do.
For all practical purposes, one could likely do just fine picking 3-10 funds from Vanguard or Fidelity and rebalancing periodically. But I was looking at their list of funds recently, and it quickly made my head spin. So I could either ignorantly just say, “Hmm, S&P500, and whole market, now a bond fund…” And that would likely be “good enough.” You could look up various recommendations to guide which percentages to keep in stocks/bonds/cash given your stage in life.
One of the benefits with diversifying within one family of funds is you get 1 statement. How complicated do you want your records to be?
I’m nearing retirement, and keep getting invites from money guys who have seminars and give some consultation - wanting my IRA. We’ve been talking with 2, mainly to attain their expertise re: my government retirement - an area that is not my current guy’s expertise. And what they say is completely different. The one guy is strongly in favor of annuities, and generally wants 2.5%. The other guy urges VERY active management - switching in/out of stocks/cash/etc - even several times a day. Both claim they greatly beat the market. Our current guy is more of a conservative buy and hold guy. (We like to keep transactions limited, because my job requires ongoing transaction disclosures of every purchase/sale.)
I tend to like our current guy, but when we look back, we took a big hit in 08 when we had 3 kids in college and failed to move $ out of stocks. So I don’t know how much I really trust him should there be any huge volatility in the future… But he has us buy individual stocks, funds, bonds, bond funds, preferred stocks… He has his reasons, but I would never have heard of some of these things I own shares in. And over 15-20 years, the balance has been growing nicely.
EVERY guy you talk to will say they beat the market. Color me dubious. Is that like Lake Woebegon where all of the children are above average? 
The other thing I’m having problems with is - how much does it matter? Hear me out here. We succeeded in being frugal, such that we now have a comfortable amount of savings/investments - and I stuck with a soul-sucking job which will provide a pension. EVERY guy we speak with projects that we can continue our current lifestyle, and will die with significantly more than we currently have.
But - if you have $1 million now, and everyone says you’ll die with $2 million - should you try to make that $3 million (or more?) How much risk are you willing to take on? Ad what recourse do you have should things not turn out so rosy?
So how much does it matter which guy I go with? How important is it for me to leave my kids 10, 20, x% more than the tidy amount I would leave them with any approach? Meanwhile, I’m trying to figure out the value of Roth conversions, guessing what my minimum withdrawals will be at what tax rates… I’d rather be cleaning toilets than try to figure out that shit.
Then, there is the issue of - if you want to go with a guy, how do you pick the RIGHT guy? How long will you need to sit down with someone before you can decide whether you trust them with a significant portion of your wealth and security? How many guys do you need to talk to before you find THE RIGHT ONE. I’m going thru the process right now, and I’m not sure how to make the decision, or how much more thought and effort I ought to put into it.
One thing that I like about my guy is that he IS associated with a bank. He moved to this bank after his old association - Merrill/BoA - was pushing him to sell their services. But, if a guy is NOT backed by someone bigger, what is your protection if he steals your $ and then steps in front of a train (which happened to a friend of ours.)
Sorry for the lack of a clear opinion. I find my money guy worthwhile, because I HATE dealing with investments. And, he likely is not perfect or the best, but he has more expertise in investments and planing that my wife and I have or care to attain. Worth 1% to me. YMMV.