There are so many variables. How often is it washed, how is it washed, how is it dried, are there pets in the home that also sleep on the quilt, is the quilt exposed to a lot of direct sunlight?
My two oldest quilts (been in use, not counting years in the making) are probably about 20 years old. One is in a guest room, always on the bed but rarely used and I can count the number of times it has been washed as less than 10. I am pretty sure I have dried in the dryer as well as on the line. The fabrics were from Jo Anne. It faded horribly in a very short period of time, exposed to sun in late afternoon. Some of the fabrics have worn through in places but overall it is in very good shape. all hand quilted, poly batting.
The other sees more use, it is on my bed and is pretty much used year round but has other quilts layered on top of it in winter. I have 4 cats that are also allowed on the bed. It has been washed numerous times but still probably less than 30 times. Most washing has involved line drying only, no tumble dry. It is also hand quilted, poly batting and JAF. It also faded in spots but because shades are drawn in my b/r fading is not as bad. The binding was done on straight of grain and needs to be replaced but other than that it is in very good shape.
My one LA quilted quilt that is in pretty regular use is only 4 or 5 years old. It is all LQS fabrics, 80/20 batting and it looks good as new. Again I don't wash my quilts all the time. Unless they are soiled I probably only wash a couple times per year. And try to do it when I can line dry them. There are sheets between my grubby body and the quilt and my cats are indoor only so they aren't getting any dirt on them, but they do deposit cat hair which I regularly shake out.