This is general information about how service contracts and warranties tend to work, not legal advice. A lawyer can read a specific agreement and tell you what it means for you. What follows is a plain guide to the parts of the paper that govern how it ends.
Read the cancellation section first
Most agreements say who may cancel, usually the buyer, sometimes the provider, and in what form. Look for whether notice must be in writing, which address it must go to, and whether a phone call counts. Find the effective date of cancellation. Some agreements end coverage the moment notice is received, and others end it at the close of a billing period. Those are different results, and the paper should say which one applies.
Look for the refund method. Some agreements refund the unused part of the term, some refund nothing, and some state a formula. Read the formula in full. Ask how long a refund takes and by what method it is paid. Ask whether any part of the refund is kept as a fee, and ask for that fee to be stated in writing before you sign.
Read the transfer section next
Transfer language covers what happens when the home is sold or the agreement is assigned to someone else. Check whether the new owner must register, and by what deadline. Check whether coverage continues on the closing day, or only after a registration is accepted. Check whether a transfer fee applies, and ask for the amount in writing. Check which exclusions carry over to the new owner.
Questions to ask before you sign
Ask who signs a cancellation and whether the provider will confirm it in writing. Ask what happens to a claim that is open on the day of cancellation. Ask whether the agreement changes its terms at the end of the term, and how you would be told. Ask which parts of the paper you can change and which parts only the provider can change.
How to compare
Put the cancellation and transfer paragraphs side by side for each agreement you are considering. Note where each one is silent. Silence is information. Do not assume that a term not mentioned is available to you.
The published figures for each system on this site are in the tables and pages of this index. They describe typical service life and planning windows, not any particular agreement. Use them to set your expectations, and use the written contract to settle the terms.