It is very important before you buy a pre-owned home, to get an estimate of the cost of renovating it, from an engineer or professional contractor specialized in renovations.
The cost of repairs of course depends on the work you will want to do.
The large volume of repairs - renovations ranges from 100-300 € / m2, with the exception of very minor repairs (eg only paintings). The point is, however, that a decent interior or exterior renovation gives a surplus value to the property and makes it easier to sell or very easy to rent, and as a result the owner gains a lot.
Especially in investment properties, the period a property remains vacant reduces its profitability.