A pitch gauge is an absolute must for collective pitch helicopters. It is unlikely you will be able to properly setup your non-micro CP heli to hover without using a pitch gauge.
For microhelis, MJP Carbon makes a microheli main blade pitch gauge. It is available from DeeTee Enterprises.
Ikarus makes a pitch gauge specifically for the ECO 8. For other non-micro helis, Century Helicopter Products makes a decent pitch gauge.
If you don't buy a blade balancer, it is still possible to balance the blades using a dowel or other method, but a good blade balancer makes the job much easier.
The KSJ-528 blade balancer works well. The Koll Rotor Pro is better than the KSJ-528 but is overkill unless you're doing advanced flying.
I highly recommend CAing the tip of a sewing pin to the pointer of the KSJ-528 to make the scale easier to read.
This is very handy for ensuring your paddles are completely flat relative to each other. For non-micro helicopters, the KSJ-624 paddle gauge works well.
In order to balance the rotor head, you need a prop balancer. The Du-bro "Tru-spin prop balancer" works well because you can hang the rotor head over the edge of a table when balancing he rotor head.
There are about three tachometers in wide use for helicopters.
The first is the Anderson Hobby tachometer. This is fairly cheap (about $35) and works well on the ECO/Logo, but it does NOT work on micro helis such as the Piccolo CP! It also drains batteries quickly even when not turned on, so I recommend removing the battery when not in use.
The second is the X-cell optical tachometer. This is expensive (about $150) but works with almost any helicopter. It only reads to 1990 rpm, so it may not be suitable for micro helicopters which typically need 2000+ rpm of headspeed.
The third is the Tera tachometer distributed by Thunder Tiger. This is a very nice digital tachometer specifically for helicopters which will clip onto the tail boom for hands-free measuring of the headspeed.
There are other tachometers, including:
Magnum mini-tach. Price is about $35.
Hangar 9 micro digital tach
Thunder Tiger 2642 mini tachometer
The shadow of the rotor blade should fall on the tachometer sensor for best results. Therefore, the tachometer should be under the rotating plane of blades.
It is a good idea to build a stand for the tachometer or to tie it to a tent stake so you can stand a safe distance away from the rotor blades and read the tachometer display.
Tachometers will not work indoors with fluorescent lighting, because fluorescent lights flicker at 50 or 60 Hz which interferes with detecting the main rotor blade shadow. You must use either incandescent lighting or natural sunlight.