Here is my best argument for specialization: knowledge is power!
Do you know that BMW 3 series cars from the early 2000 have a “no reverse” problem. Automatic transmissions simply lose their reverse gear. The transmission is shot. And you basically need a new transmission or costly repairs – like $2500+. So, many people will sell these BMWs for almost nothing – like less than $1000. They assume its a blown transmission. But did you know that BMW had two different transmissions during this time period: one made by ZF, the other made by GM. Now here is the specialist secret. The ‘no reverse” in the ZF tranmission IS likely a serious failure. Its a massive design flaw that led to a class-action law-suit. OK, so here is the insider information. The GM transmission can also ‘lose’ it’s reverse. Same symtom, BUT . .. entirely different cause.
You see, it was common to lose reverse in the GMs for this simple reason: the filter in the reverse solenoid would become clogged. So how is it fixed? Is it a $2500 repair like the ZF?!?!? Not even close. Simply get the transmission fluid changed and ask them to simple clean the screen on the reverse solenoid. It’s maybe a $100-$200 job!!!
My point is not to tell you to simply buy BMWs.
My point is this: knowledge=power=$$$
Profit from your insider knowledge!