[TEL N KEL]

All depends when you intend to use the pool, which way the pool is facing and on the individual person using the pool.
I would say yes for October.
We go September and do not have pool heat but have on some occasions thought we should of had it.
Early morning dips can be chilly in the water even though it is warm.

You need to weigh up the cost against possible usage.
How much do you intend to use the pool ? If like some families who may spend days around the pool with kids jumping in and out then it would be well worth the extra.

If you are only intending to take a dip when and if you feel like it then it would be a waste of cash.

Also remember when the pool heat is turned on it does not instantly heat your pool so if it has not been used by previous guests your pool may still feel like there is no heat for about 2 days.