In practice, many advisors charge 1% of assets managed, which may not sound like much. But the reality is a bit surprising: A 1% fee applied on a $1 million balance is $10,000 per year, and the fee will increase proportionally as the account balance increases. Over time, and due to the nature of compound interest and earnings, fees can really add up.
Other advisors may have different fee structures, which may vary depending on whether they actually manage money for you. Some advisors may charge trading commissions on any orders they place on your behalf, while others may have more bespoke cost arrangements.
Fee-only financial planners, on the other hand, may charge you on an hourly basis for as-needed advice, or they may charge a fixed-fee retainer for ongoing access to advice. Other planners might also be willing to work on a project basis, depending on the depth and complexity of your needs.
The only way to know is to ask -- but be sure you understand the dollar amount you're paying for any service. Don't be satisfied with just a percentage amount!