AC near the end of life expentancy when closing

[Chase Gu]

Hi, Everyone! I am looking at a 4-unit apartment building. AC and water heater in all four units are over 25 years old. They are working but may need replacement at any time. Seller is unwilling to replace because they are working. What would you do in this case? Would you ask for credit? If so, would you ask for 50% of the total costs or some other percent? 

Also this property has a small retail space, with an existing tenant. Can I force the tenant out when I close? How difficult is it to evict a commercial tenant (this is in VA)?

Thanks!