I know what color new oil is when I pour it in. That tells me that the old oil had a ton of impurities suspended in it, which is one of the reasons why you change motor oil. The motor oil itself might still be OK, but why keep particulates circulating around your engine for so long? I'm not working extra to pay for another engine or another car!
YUP. I had Quick Lube change mine as I used to do at times. (bring my own oil and filter) That time for some reason the oil looked dark right away on dip stick and under the oil cap. ****** me off cause I started to think "did that tech pour my new clean oil in his generic "dirty" plastic measure bottle (as I see them do sometimes) or did he use a nasty funnel? or did he not wait to drain all the old out etc..." It bothered me so much I paid my nephew a few days later to do it again! That was money down the drain so I change oil at home all the time now. Well , nephew does since I can't anymore. We get to visit, talk sports , autos and life and I make him take some cash for helping his UncleSam.