Define the acquisition route and review period
Start with the exact candidate and extension in your private notes, not a generic extension price. Distinguish an available registration, an aftermarket purchase from a current holder, and a transfer between registrars. These are different events. A registrar transfer quote is not a seller's purchase price, and an asking price does not establish that an agreement or acquisition is available.
Choose the period you want to inspect and write its end date. Record the quote currency and when you checked it. A multi-year holding scenario is a planning assumption, not a prediction of how long the domain will take to sell. Keep the original currency beside each quote; do not silently combine amounts in different currencies or assume today's exchange rate will apply later.