The four year degree is treated as the safe option and the thing you do if you are unsure. It is a large commitment and it deserves to be chosen rather than defaulted into.
A dwelling limit set when the policy was written and never revisited is the most common form of under-insurance, and the clause that enforces it is easy to miss.
Legal work is priced three ways and the quote you receive tells you what kind of problem the attorney thinks you have. That is useful information by itself.