A-million-dollar question. It depends on the cultures within a school. I have seen the Principal circulating the names amongst HODs and asking them about their opinions (for SH positions). There are schools where HODs will propose because they want to handpick their assistants. My current P would do the planning on his own. The HODs could propose but he has his own pick.

Usual spiel - a good fit the school culture, a good team leader, good at culture building etc.

Covering/Internal for One Year - Necessary for some KPs especially if it's a non-IP position. They do need to write about their contributions and vision for that portfolio. Plus, some Cluster Sup may question the person in depth.

Covering for Two Years - Some KPs may be deemed not doing enough for confirmation. I have seen my previous P stretching the appt for 2 years.

Covering for more than Two Years - the best advice is to ask your friend to have an honest conversation with VPs or P. They might keep him because he is vain enough to assume the half-baked position (I know some teachers take pride in being a KP - covering or not). In actual fact, the SLs don't think he is suitable for that position but is too lazy to identify someone else. My colleague just stepped down from a covering position after 2 years because my P told him that the school din intend to confirm him based on his attitude/contribution to school as a covering KP.

Is it rosy up there? It depends!

My friend, who was a HOD for 7 years, was capped at GEO 5 for the longest time because she was advised that getting that promotion to SEO 1 would disadvantage her in ranking (???!!!). She also stepped down after her SH was promoted to SEO. I have friends who are stuck in GEO 4 for 6 years despite assuming a KP role for 5 years. Some schools do not intend to promote.

If your school has the culture of stifling promotion, do not assume the KP role. Declare tuition and earn better money elsewhere. If your school has the culture of matching the substantive grade to your KP position, then do consider because the pay does make a difference. Sadly, the schools in the latter category are few and far between. The very very top schools would do that to keep their good people. If not, do not be vain enough to take on any KP position.