Does Substitute last longer if you have more HP or Defense?

Question

what makes substitute last longer more hp or more defense or both?

Answer 1

Using 25% of its maximum HP, the user creates a Substitute with 1 HP more than the amount of HP lost by the user.

The substitute will break when the damage the substitute has taken is greater than the HP used to make it.

Source: Bulbapedia

So both (Sp)Defense and HP.

HP so your Substitute has some significant amount of life & (Sp)Defense to lose less HP each turn.
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BTW, an interesting point.

A one-hit KO move, if it hits, will always break a Substitute.

Comments

Also note that more HP results in a greater cost of making a sub, so if it breaks on a hit, you will be technically taking more damage.

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Lolz yea. Blissey Ev trained to max in HP has 714 HP. That means a sub costs 178 points!!