If you are a doer whether it be a craft or something you make or build , the best advice I ever had was to use the best materials you can get. It applies to almost everything.
In spinning , it can sometimes be hard to get good fleece. Friends can be very helpful & often I am given fibre that they have either excess to their needs , that has been donated at my Guild , or that someone wants to get rid of because they don't know what to do with it. The latter is not always a good one. I have had alpaca fibre given to me that was not nice. It was full of skin bits stuck to the fibre shaft. Totally unusable unless you either picked it all off or cut it out. Not very nice anyway & I later found out that it had most likely been sheered off a dead animal. Another one was a collection of fleeces that had come from someone starting up in sheep. It was their first clip & not brilliantly done. The Southdown was very short & open but with lots of short cuts. The Jacob was felted. In hindsight I should have thrown this fleece away , but I wanted to see if it could be processed & how hard it would be. Also the owner wanted a little something back in exchange for the fleece.