Manchester tests much more than just twice a year. Plus, they pretty much take who passes. Which because of the process, is very few. I took a Londonderry test that had 100+ applicants and only 5 passed. Manchester's test pools are usually that big.
Manchester is always hiring,but thats because they have a huge budget, and they do have an aging force. Not to mention they have the huge community policing movement going on with their new chief. Looks like their are lots of changes on the horizon for the department, let alone the city! Best way to find out how many they want to hire, is to look at the town/ city stat reports.. look at the department #s that they are staffed for,and then look at the actual #s they have on. That will give you a good idea of how many they are looking for.
ManchVegas PD has been hiring up to 10 at a time. Recently there has been a slew of retirements and a bump up in the compliment of Officers (total number of Officers is around 225, including the brass). So the test has been given more then twice a year. Usually there is approximately 100 to 150 people signed up for it. There is a multiple choice test (common sense) and a PT Test (push-ups, sit-ups, sit and reach, bench press and 1.5 mile run) on the first day. This usually weeds out a large group, If you pass, the background begins. This includes an oral board (you and two Officers), a psych test, physical, and a polygraph (unlike MA). If you pass all these and given an interview with the Chief, you are on the way to a job, usually. The pay and retirement are pretty good (MPD has it's own pay scale and the retirment is State of NH Group 2 Police and Fire - 20 years and/or 45 years of age at 50% of your highest three years including O.T. and details). Once hired and a graduate of the NH PSTC (Police Academy in Concord) you will be assigned to the Patrol Section. There is the chance for advancement into a specialty, including K-9 (10 dogs), Traffic, Juvenile, SRT (SWAT), Detectives, and Community Policing (includes PAL Officer, 2 Horses, Crime Prevention).