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The lease usually states if there is an obligation to set up a reserve fund and may allow for contributions to it but if the lease does not have a provision for a reserve fund, then you would not be obliged unless there's a variation in the lease to allow for this, and this can only be achieved if all the parties agree to the changes. If your lease does not already have a reserve fund then you do not have to contribute, so you'll just need to check the lease first before knowing. You do not have to pay anything that is not included in your lease.
I hope this help and would be grateful for a positive rating, thank you. John