Porsches and Toothbrushes

What do toothbrush brands and Porsches have in common? Both have product lines that are largely undifferentiated. For the latter that is an asset; for the former not so much. 
 
If you are a layman when it comes to the technical side of sports cars most Porsches look pretty similar. The difference is in the performance. 
 
The same goes for toothbrushes. Each brand has a relatively distinct look compared to other brands, but little variability within the product line. This becomes a problem when I need a new toothbrush but forget the kind I bought the last time. 
 
Porsche doesn’t have to worry about this because a guy who wants one only needs to worry about his price point and the performance he requires. He knows that he wants Boxster or 911 Turbo depending on how much he’s willing to spend. 
 
If you’re Porsche you keep doing the same thing. People who know about cars know exactly what you’re driving even if it looks the same from some distance. If you’re selling toothbrushes, maybe you use some subtle branding (a number system on the product, not just the package?) to make it easier for gents like me to get those hard to reach places.