I think a good squeegee is an important investment for anyone screenprinting. 
This simple tool can affect the overall quality of the end product,
so I thought it might be useful to give a little advice
to help select a good squeegee appropriate to your task:

Handles & Blades: What are they made of? 

Squeegee 'handles' are most often made from wood,
although aluminium or plastic handles can be a little easier to clean.
Also consider whether the shape of the handle
will be comfortable to hold if printing for long periods of time.

Squeegee 'blades' are made from 2 basic types of materials: rubber or polyurethane.

The least expensive squeegees are usually made of rubber
There are natural rubber and also synthetic rubber blades.
While commonly used in education and hobby printmakers,
rubber tends wear more quickly and is not as resistance to strong solvents.
Although I periodically sharpen the blades on a belt sander,
the blades can also be replaced fairly cheaply after many years of use.
As a rough guideline, rubber squeegees usually cost around NZ$1 per cm.

Polyurethane, a synthetic plastic material, is more expensive, 
 but it offers the best resistance to both physical and chemical abrasion.
It is often used to make squeegees for high-use and for automated equipment.
They almost never go blunt and especially good if using solvent-based inks.
Polyurethane squeegees usually cost approximately NZ$2.50 per cm.

Squeegee Durometer: How hard is the blade? 

The blade needs to be rigid enough to shear the ink through the screen, 
yet needs to be soft enough to adapt to the contour of the surface.

The durometer indicates the physical hardness of the squeegee blade.
The most widely used measurement for squeegee material is the Shore A scale.
The lower the shore rating the softer and more flexible it is, higher ratings are harder.
For example, we will say 60 = soft, 70 = medium, 80 = hard, and 90 = extra hard.
A durometer or 'shore' of 70A is considered industry standard.

Typically the substrate and the screen mesh will determine the durometer selected.
Ink choice is also an added factor to consider:

UV-cured inks cause more harm to the blade than plastisol or water-based inks. 
 The denser the material, the more solvent-resistant the blade will be.

For example, if the substrate has an irregular or rough surface and requires a coarse mesh,
 then a softer squeegee, with a durometer between 60-70A, could be used.
If the substrate is smooth and a finer mesh count is being used,
then a harder squeegee, between 80-90A, could be used.

Squeegee Profile: What Shape? 

Over time manufacturers have also made squeegee blades with different profiles.
The profile determines the thickness of the ink deposit laid down on different substrates.
Squeegees with a square edge are the most common, and mainly used.

Rounded Squeegees are used the textile industry when a very heavy deposit is required,
and you will notice as your squeegee gets blunter the fine decreases.
Beveled Blades are used for printing rounded surfaces where fine definition is required. 
 But for most of us in art & industry, square is best!

Area Coverage: How Long?

I usually recommend that you consider 2 main measurements:
 the usual size of the images you are going to print,
and also the size of your screens.
I try to allow approximately 5cm more than my image width as a guide,
but also need to allow about 5cm smaller than the inner frame dimension
to allow ease of printing without hitting the sides too often.
For example, I use 35cm squeegees for all A4-A3 sized jobs
(which is anything on a 50x60cm screen).
I also have a 15cm squeegees for smaller jobs, and 50cm & 80cm for larger screen jobs.

Maintenance & Storage:

When printing you should aim to use for less than 4 hours on each side of the blade.
  Printing continuously with the same squeegee edge
can cause swelling and softening of the blade.
If ink residue begins to build up on the inside of the screen,
replace your squeegee with a different one more often, or use several squeegees in rotation.

Resharpening can be performed by many methods.
For rubber squeegees I usually use a belt sander 
or shave off the end with a rotating saw blade (sounds dramatic!).
You can also recycle the handles by buying just the replacement rubber for $40 per m.
Polyurethane blades could 'melt' using these methods, 
so I'd recommend professional advice should be sought before sharpening them.
Continual sharpening of the blade will reduce the blade height 
and eventually this will affect the performance.

Squeegees should be laid flat when not in use, not leaning on their blade.
If left leaning on the blade it can develop a 'wave' where pressure is applied.
Squeegees should be stored dry, and away of heat or direct sunlight. 
If you have several squeegees then invest in a 'rack'
or simply drill a hole in the end and hang by a nail on the wall.


For the non-commercial hobby printmaker
you will get many many years of use of joyous printing from your squeegee
so it is definitely worth the investment in getting the right tool for the job!