The consensus, and what I advise my clients, is as follows:
For the non-professional, I tell them to keep a strict record of their time and to figure somewhere between $25 and $50 per hour (a typical fee for a professional trustee with training, bonding, and expertise is around $100 per hour). Then I advise them to look at the complexity of the issues they were required to deal with. The more straight forward everything is and the more helpful and cooperative everyone is, to lean toward the lower figure and to a higher number if the opposite is true. I tell them to realize that, if they are a beneficiary, part of the fee is coming from their own, otherwise income tax- free funds, and the fee now becomes ordinary income for income tax purposes.
Whichever rate they choose to compute the fee, I then tell them to compare it to a fee of one percent of the trust estate. If they are under that figure, they are in the ballpark. If over, they need to determine how they can rationalize the fee in light of the fact that a judge, who might be called upon to review it, will examine an excessive fee very critically.
I tell trustees that they are probably also fine taking a flat one percent fee that should be set forth in their accounting, but they might also be creating a situation that will be more likely to cause a court review at the request of a beneficiary. For example, it probably will not look good to take a one percent fee on a trust estate with few debts and the only asset being a $1M CD.
In any event, the rate charged for the fee; the basis for the fee; and, the final amount, should all be set out and explained in the accounting to beneficiaries.