Hot Tub Jets
Jets need to be suitable for the part of the body they are aiming at and deliver the right amount of hydro-therapy.
There are usually several different types of jet built into modern hot tubs such as rotating jet, directional jets and pulsating jets. A hot tub might be sold as having 50 jets but if those outlets deliver poor, uncomfortable or even downright painful streams of water then they are next to useless. The best way to see if the jet array is right for you is to take a "wet test" - that way you will know for certain if the jet system is right for you.
All of the jets should be able to simultaneously deliver a vigorous massage, if required, without resorting to diverters (a diverter means the pump can't run all the jets at once and has to split the hot tub into zones - they can also can reduce the efficiency of the pump by causing restrictions).
If the hot tub has a separate air blower system ensure that it gets used regularly or is programmed to activate occasionally to ensure there is no bacterial build up within the pipework.