If you could spend 10 minutes cruising at e higher optimum altitude then it would be worth it.
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Another 'ancient' rule of thumb is 'Do not climb unless you are more than 1 hour from landing'.
Just rules of thumb, yes. The problems all thumbs are not same ( and bit crooked)
Even those 10 min or 1 hr will make you loose fuel if you start your descent early or late ( twice as much if late)...(ToD point depends on GW, wind, RWY change, descent-speed, cabin descent rate... )
If ToD is correct, even 1 sec on cruise ( not 10 min) will save fuel.