Zero throttle on jumping is essential. I have other things to while playing elite so zeroing the throttle means I don't ram a star if I've been diverted while doing that something else. It guarantees safe entry.
"Other things to do" every 30-40 seconds?
No... Zero throttle is NOT "essential". It actually works against you. It may be beneficial if you are not willing to pay attention - but its certainly NOT essential or efficient.
I've never done it and I've never had to. Even the ships with the poorest maneuverability can be turned away from the star when you jump in.
In fact, if you are throttling down, I expect your jumps are taking a lot longer than necessary. Without reducing throttle, you can do a complete jump cycle every 30-40 seconds.
You will also lose a significant amount of speed when you enter your final destination system - speed that's very hard to get back that close to the main star. So, if you're throttling down on your last jump, then you are going to pay heavily in the transit time to your arrival point.
Throttle up, start your jump sequence, and you should never have to throttle back down until you get to 7 LS from your final destination...
Never had a problem with any star I have ever jumped in/to/around in almost 1000 hrs of game play... If there is truly something that dangerous in your route then you might consider filtering it out of your route plotting. Otherwise you are paying a penalty on EVERY jump...