No matter what, a tach is a tool to be used as necessary, but not absolutely necessary for flight. Proper tuning can be attained without one.

They are handy to have in your flight box and can help under certain circumstances, however, it is not required, just nice to have.

The price of the combination tach/ESV is a good thing but it is a bit pricey if you are watching your $$$. If it doesn't matter to you, then, hey, it's a great combination.

I have the second item, the tach only, and it comes in handy at times, but I tune by ear and seldom go to the tach unless I change props. Then I use it to see where the engine is at max throttle. My goal is not to over-rev the engine if I lower the pitch, and that's about it.

Lots of folks will say that it's required for four stroke engines, but others will say it's unnecessary. I don't own a four stroke so I can't comment on that, but from what I've read from other poster comments, again, it's not required, just nice to have.

More advanced pilots, Pattern folks, for instance, can tell from the sound and the tach how their engines are running. Most of us are not that advanced, and can tune them by ear just fine for our purposes.

Remember, this is a beginners forum, and advice passed here is for beginner to intermediate pilots.

CGr.