If you have put an offer on a house, and through the contigency inspections, you have found deferred maintenance or repair costs for damage, you may need to renegotiate depending on the items found and whether or not they were disclosed.
As far as the percentages compared to price, price is completely different from value. Price can be the cost to replace new which may or may not add value to the home. Maintenance would clearly depend on the item. Some items in a home cost more to maintain than others. Pools would be one item to fall in this area. Certain features of a home add value while cost low in price while other items could have an expensive price but have a decreased value, over improvement would fall into this category.
Arriving at the value of a home in today’s market place can be achieved by consulting an agent to review comparable data of solds in your area to determine what price the home might be valued for with similar features, location, and age of home.