Removing flower buds to promote healthy plants?

[khabbab]

I always remove the early flowering buds of pansy, petunia, ranunculus and many other annuals to have a bushy and healthy plants. I have 2 questions:

1- This technique is good for all annuals? This technique did not work for me on chrysanthemum in pot but tomatoes very successful(indeterminate).
2- How do i know that enough pinching, let the plant flower now.
3- Not applicable to perennials which start flowering at very small age?