You spend on it, what it is worth to you. If you don't think it's worth spending a lot, you don't. If you do, you do.
I think certain things are worth paying quality for and others, well you don't have to. My clothes don't need to be expensive, nor do my shoes. I don't know, it's all relative.
"Things look different from the seat of a bike carrying a sleeping bag with a cold beer tucked inside." ~Jim Malusa
2009 Trek 520-Brooks B-17 Special in Antique Brown
2010 Surly Long Haul Trucker-Brooks B-17 Standard in Black
1983 Fuji Espree Single Speed-Brooks B17 British Racing Green