About price negotiation for second hand places;
On second hand places in multiple ownership (like a block of apartments) the owners often pay about 1% per year into a renovation/repair fund.
If the place you are buying does not have a renovation/repair fund then it is usual to ask for a 1% price reduction for each year since it was built or had a major renovation.
Like with any other negotiation you are not guaranteed an agreed price reduction but even if you do not get the full amount you can find this is a good lever towards getting a decent price reduction.