Paying for a service contract is one way to prepare for a major failure. Keeping money aside for repairs is the other. The two approaches handle the same major pile from the earlier sorting, so compare them directly rather than treating the contract as the only option.
How a reserve works
A repair reserve is money you keep in a separate account and do not spend on routine items. You set a target for yourself in writing, decide in advance when the money may be used, and check the balance on a fixed schedule. The reserve has no contract terms of its own, so its limits are the ones you set.
How a contract works
A contract moves the risk of a covered failure to the administrator for the price you paid, subject to the terms written in the signed paper. The contract adds its own terms: a waiting period, a cap, exclusions, a claim route, and cancellation and transfer rules. Each of those changes what the contract does in practice.
Questions to answer on paper
How long do you plan to keep the item? Could a major failure come early or late in your ownership? Would you be able to pay a shop yourself and wait for money to come back, or would that strain the household? Does the contract require a particular shop or approval step, and is that shop within reach of where the item is used? Write each answer down before you compare the two routes.
Where to start in your state
The state pages on this site name the regulator and the statute for each state, say whether a roster is printed, and list the rules this edition has read. For example, the Alabama service contract rules and roster page is the starting point for a reader in that state.
What this guide has not read
This guide does not say which approach any state requires or prefers, and it does not rank a reserve against a contract. It has not read the rules for every state, and the state pages say which states this edition has not read. Check the rules for your own state before you rely on either approach.