When asked: "What would you do if your Java app experiences long GC pauses?" — most people would answer: "increase the heap size and/or tune the garbage collector." That works in many but not all situations. The heap may already be close to the total memory available. And GC tuning, beyond a few most obvious and efficient flags, often becomes a black art where each new change brings a smaller improvement. Worse, hyper-tuning GC makes it tightly coupled with your current heap size, number of CPUs, and workload patterns.
Need help choosing the right GC? Check out this post!
If any of these components changes in the future, the GC may suddenly perform much worse. And (what a surprise!) at that point, it may be really hard to remember why each of the flags in the combination like the one below is there, and what its effect was supposed to be: