In my 23 years working on lasers, there was only one machine that needed more than glass and optics because of bad gas. Most just needed the optics cleaned. In the worst case, the heat exchangers would probably need to be replaced or cleaned as well as replacing the glass and optics. I've never had to change a blower from contaminated gas.
As far as operating cost, lasers that cost less to purchase/operate usually produce less. Best advice is to talk to as many people as possible and see what experience they've had. In addition to cost and production rate, there are many things to consider, i.e.-
How many parts of the machine are made by the manufacturer? Are they building a complete system in house or are they buying resonators, controls, whatever, bolting them together and slapping their name on it?
Can all maintenance be done by the user? Or does the machine require periodic factory service?
Can a user buy any replacement part they need or do certain parts have to be replaced by a factory rep?
Laserninja- you mentioned the Amada uses a lot of n2 but I don’t see it anywhere in your cost per hour sheet. Which brings me to another point, the cost per hour varies widely depending on what you plan on doing with your laser.
Buying a laser isn’t easy, do your homework and talk to as many users as possible.
Chris Krug