Originally Posted by kragster
....And technique comes down to practice. And you only practice something if you think the time spent is worth the effort....
No it does not. Practice is only one aspect of it. Acknowledging where you are and where you want to be with regards to technique and having the aptitude, plus often the support person (coach), around you to make the changes, work on them until they stick and come naturally is what it takes to improve technique. And since perfect technique is basically a unicorn of learning the target you're aiming for is often quite blurry - more a general move in the direction you think will result in an improvement.
Failings in this area are the norm, not the exception, and why the vast majority of tennis players globally never really improve much - they just get more honed at what they've got.
Take Nadal as an example. No amount of practising that he could practically undertake would make his backhand volley great
- he would most likely just mitigate the shortcomings of it. To make it great he would need to change how
he hits it, not how much he practices.