Professional Development

As many people in the profession of public administration make it a point to better themselves professionally, I ask - what is the best form?  In person?  Online?  Mix? Group?  1:1?  Self-paced? What about subject-matter - finance?  HR?  Leadership? Work-life stuff? Communication?  Amount - a little or a lot?   Blocked or periodically scheduled on the regular? The answer is -  it depends on the person as each individual tends to learn differently.