My strategy when making Archviz models if that if they’re going to be used several times in a level, I optimize the models pretty hard, but if they’re just going to appear once or twice, I don’t do that much optimizing. In the project I’m working on atm, I have many objects with 10k-60k polys, and one or two with 100k-150k. 70k for a piano is unnecessary though. For instance, you could replace all the white keys with a box with normal maps instead. Only use many polygons where it will affect the shape of the object, and remove the polys that don’t contribute anything. I think you should be able to get that piano to 10-15k without any loss of visual quality.