All-season vs. lightweight vs. winter, which weight should I buy?

Reviewers across mainstream tech press and Reddit converge on the same advice: if you keep your bedroom 65–70°F year-round, an all-season (medium) weight is the safe default. Hot sleepers and warm climates lean toward a lightweight or summer-weight insert; cold sleepers in unheated rooms should size up to a winter-weight or higher fill weight.