に越したことはない: the preferable choice if possible
Distinguish a binding requirement from a choice recommended as safer or more advantageous. Check negative preceding clauses and connections with nouns and adjectives.
That option is better if possible
準備は早く始めるに越したことはありません。 says it is best to start preparing early. It emphasizes the advantage rather than claiming that starting later makes success absolutely impossible.
The expression recommends a safer or more advantageous condition. 荷物は軽いに越したことはありません。 says that lighter luggage is preferable; it does not prohibit bringing heavy luggage.
Connections and the direction of negation
Verbs and i-adjectives connect in plain forms. 無理をしないに越したことはありません。 says it is best not to overdo things. The recommended action is the negative content 無理をしない.
Nouns and na-adjectives can use である, as in 健康であるに越したことはない and 安全であるに越したことはない. Identify the state being recommended rather than interpreting the ending simply as absence.
Separate duty from a report of action
締め切りまでに出さなければなりません。 requires submission by the deadline. 早めに出すに越したことはありません。 recommends submitting early. The requirement and recommendation can both hold.
確認するに越したことはありません。 judges checking to be preferable; it does not report a check already completed. Read the advice separately from whether the action occurred.
Quick check: Does 道は混まないに越したことはありません。 predict that traffic will definitely be congested?
Show the answer and why
No. It evaluates a lack of congestion as preferable. It neither predicts nor confirms actual traffic conditions.