With real estate it is location, location, location. With china and porcelain it's condition, condition, condition. There are some exceptions, where a pattern is extremely rare. Your family may have been using it for years, but the person who is going to buy your piece doesn't want the defects.
So what affects the value of a piece?
- Chips
- Cracks
- Crazing
- Wear
Small nicks or chips to pieces generally get put into the donation pile unless they are a foot of a tureen or large item, but the value is hugely decreased.
Cracks – if it has been repaired – put it in the donation pile. If it's a hairline crack on a larger piece, again the value is hugely decreased.
Crazing – These are like the spider web like lines that can appear on porcelain and china. 
This occurs during manufacturing when the glaze is applied, and during the cooling process the glaze gets slightly cracked. This is very common on older American porcelain, and some Ironstone pieces. You can see an example of crazing to the right. Over time these cracks get oils in them that over time become discolored. Depending on the extent they can severely decrease the value or even put into the donate pile.
Wear – some pieces have been used and show significant wear to the design or pattern. These generally go in the donation pile depending on the age. Again, the value is decreased with any significant wear.
So, basically, go through every piece, and put aside all the items with chips, cracks, crazing or wear and see what you have left. The family may have started with a full 12 piece setting of fine china with all the serving pieces, but it is not unusual to only have a true 8 piece setting left.
For all of the articles in this series, What is my china worth?, check out the links below.
Part 1 – What is my China worth – Introduction
Part 2 – What is my china worth – How old is it?
Part 3 – What is my china worth – Is it hand painted?
Part 4 – What is my china worth – Condition
Part 5 – What is my china worth – Pattern and decoration
