Time in the army isn't as important as the points required for the promotion. In 2011 a new promotion point scheme will be in effect that minimizes the commanders points and other "freebie points" from the older system.
A rule of thumb is that it'll take you about 30 years. 4 years of med school, 8 years of residency and 18 years to learn how to spell surgeon.
If you're smart and you behave and don't cause trouble, you can be a sergeant in two years, sometimes sooner.
a General's driver MIGHT make it in a short time, but in general it could take 12 to 20 years.
Depending on the individuals MOS (job), necessity for promotion based on the needs of the Army, their personal achievement's, prior positions held and their records it can take anywhere from 15-20 years. Typically promotion to E-9 Sergeant Major is between 14-18 years of service. The higher in rank you go the more competitive it gets because you are competing against thousands of other soldiers for less than 50 E-9 Sergeant Major slots for that year. The number of slots is based on the needs of the Army for that year.
Depending on the individuals MOS (job), necessity for promotion based on the needs of the Army, their personal achievement's, prior positions held and their records it can take anywhere from 15-20 years. Typically promotion to E-9 Sergeant Major is between 14-18 years of service. The higher in rank you go the more competitive it gets because you are competing against thousands of other soldiers for less than 50 E-9 Sergeant Major slots for that year. The number of slots is based on the needs of the Army for that year.
Technically, all officers are of a higher rank than any sergeant. Sergeant Major however, is a very high enlisted rank. A sergeant major will usually only take commands from a Lieutenant Colonel or higher.
15 yrs including police or time in the army
Better is a matter of opinion, but a sergeant major outranks a master sergeant or any other sergeant. There are other advantages in terms of pay and privilege. I am told that in the US Army only generals and sergeant majors have careers which last thirty years anymore. The rest are told to take their boots for a walk before then, even if they want to remain in service.
it took 15 years to build the terracotta army
I assume you are talking about E-8 and E-9 ranks. At E-8 you become either a First Sergeant or a Master Sergeant. If you take the First Sergeant route the next rank becomes Sergeant Major. If you take the Master Sergeant route the next rank becomes Master Gunnery Sergeant.
"How many years does it take to become a chemotherapist?"
How many years does it take to become a cytopathologist?