I'm in search of a new piano. I have tried several brands in some piano shops.

My friend previously had a Yamaha U3 and likes the Yamaha sound, so has narrowed my search to 2 pianos.

First is a 2010 Yamaha C3 that is original and in very good condition. The second is a 1990 Yamaha C5 that has new strings and hammers. 

Both pianos are in different places, so I'm unable to play and compare them next to each other, but have played the C5 next to a 2018 C3, and have played the 2002 C3 next to 1979 C3. 

My friend enjoys how loud the C5 can play as well as the bass, but is a bright piano overall and would likely need voiced lower. The C3 sounds perfect, just doesn't seem like it could be as loud (again, rooms and acoustics are totally different), but was great compared to the older C3 or even a G5 next to it. my room is 21'x20' with wood floors, but is completely open to the dining/kitchen, so is essentially 21'x40'. I like both very much and switch preferences depending on the day. Should I be concerned at all about the restringing and hammers on the C5 as well as the age? 

The C3 is $1500 more than the C5, but is almost 20 years newer. I have had a technician tell me always go with the bigger piano and age doesn’t matter, while others highly encmyaged the newer piano that had not been refurbished. 

Which piano should I buy? Thanks in advance.