Wills and trusts are both estate planning tools, but they solve different problems. A will says how probate assets should be distributed after death. A trust can hold and manage assets according to written instructions during life, incapacity, and after death.
The probate question
Probate is the court-supervised process for administering certain assets after death. A will usually goes through probate. A properly funded revocable trust may help assets pass outside probate, but the trust must actually own or be beneficiary-designated for the relevant assets.
Cost, control, and maintenance
A trust often costs more to prepare and maintain, but it can offer continuity if the creator becomes incapacitated. A will may be simpler, but it may not handle privacy or multi-stage distribution goals as neatly.