While I'll agree with Ulf on avoiding micro-optimizations - especially in
Java, where the JVM may actually rewrite code at runtime based on observed performance, from a reliability level, I recommend discarding the old list.
The days are long one when object construction was a serious consumer of resources, but it's better to start from scratch with a clean object than possibly get weird behavior due to reusing an object that wasn't cleaned out properly.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.