I furnished a flat I rented out, entirely with second hand furniture, good quality sturdy furniture, mostly bought at auction, that could survive the depredations of young people.
Furnish a flat with new cheap furniture, landlords' specials, which is widely available. and you will need to completely refurnish every year because such furniture is cheap and nasty, easily broken and impossible to repair.
When the flat was let it was freshly decorated with a new kitchen and carpets and curtains. I bought a really nice teak dining table and chairs and large shelving unit in the living room, but a new 3 piece suite. One bedroom had teak furniture, the other had freshly painted solid wood furniture.
The flat was purpose built when teak furniture was all the rage and my letting agent was more than happy with how the flat looked and was furnished.
I never had any potential tenant turn the flat down because of the furniture, nor did it ever suffer any significant damage.
My home and my children's homes both contain good quality furniture purchased from charity shops.