Contrary to popular belief, pianos unfortunately do not last forever, and parts may need to be replaced. When parts begin to break, or when they are too brittle to safely work on, replacement becomes the next step. This process can become expensive quickly, so discussion about options and what the end result would be is very important.
Replacement parts: Wood vs. Composite
In addition to determining the level of action restoration desired, we now have a choice between traditional wooden parts versus new composite materials. Composite materials have certain inherit advantages of wooden parts. Composites are not affected by humidity, and are stronger and lighter than their wooden counterparts. There may be tonal differences between wooden and composite parts, but with proper hammer choice and voicing, a suitable tone can be achieved with either choice.
Having worked with Wessel, Nickel, & Gross composite parts for several years, I have experience with the parts and how to achieve the best results with them. That being said, I understand the desire for the traditional wooden parts, and believe that the pianist should choose whatever they are most comfortable with.