sir ji keyon mazak kartay hayn aap.
my personal car at home in karachi is very very old i mean over 10 years, it is 90s' model. I purchased used from within family circle. The engine & suspension was over hauled approx 2 years ago. booked a new yaris expecting it in 2022.
all questions you asked varies with variety of parameters, there is no set scale for such changes. Specially in our country where the law for motor vehicle testing fitness and road worthiness is only on papers unknown to RTAs' and never practiced.
54 year old buses are plying on road. 57 year old toyota corona is very much owed by the same 76 year old who purchased it brand new.
all points asked have high variables in Pakistan.