Im trying to price out how much to charge for a print job, so first I suppose I would need to come up with the min number of hours before major service is typically required, i know mileage will vary but Im just looking for rough estimates so I can come up with a ballpark number. Printer in question is a 6 but I would expect there to be a lot more data out there on the older models so I any models will do.
Thanks
The marlin firmware doesn’t keep track of machine hours. I probably have a good couple thousand hours on mine now, but you probably don’t want to use mine as a reference given my hobby of taking it entirely apart on a whim every 3 weeks
I track the time used on my print jobs… I’ve had a TAZ4 frame for 16 months and have printed for about 4000 hours. During that time, I added PEI (replacing the adhesive twice), upgraded to hexagon extruder, replaced the nozzle five times, replaced the worn-out fan on my old-style TAZ 4 power supply and replaced three steppers (maybe due to dust from magnetic iron filament). The small blower on my extruder is also worn out, but they’ve been out of stock for a while so I can’t replace it. 
It’s about time to do the third replacement of the adhesive on the PEI.
Overall, hardware parts cost is pretty negligible compared to the consumables. But if you are trying to finish something on a defined schedule, the random failures will occasionally mess up your plans.
I built my Taz from a pile or two of kit Taz parts last year, so it is still pretty new. It does have about ~3K hours on it, but ‘major service’ is what I do for entertainment. So my printer is composed of pretty prime parts and very adjusted fit and function. 
In that time I have replaced 3 PEI sheets, one micro Blower fan, 2 Z couplers and one heat bed cable.
Dont get me wrong I dont mind repairing it. I was just trying to come up with a generic wear and tear cost.
Do you mean random print failures or hardware?
I am not sure what joshuanapoli was referring to, but I can give an Idea from my normal job (3D printing is just to relax from that )
As soon as you want to create income from machinery some random failure / machinery break down has to be considered.
Saying that I appreciate that you are already looking into the right direction with your question!! (where is the thumbs up emo???)
Even though I have no interest at all to charge any body for 3D prints (I have a totally different daily job) I found your question interesting enough to start some “research”. The numbers below I am sure are not really representative but I believe they can give an impression in ball parks that should be considered for a business .
It seems that even today 3D printing is still in its beginnings and there for difficult some reasonable numbers. Never the less here what I have figured:
Average MTBF (Mean Time Before Fault / Failure) for a 3D FFF Printer seems to be apr. 1800 hours.
This MTBF could be longer if there would not be spurious failures of machines. about 15% of all reports I found had a machine failure after it was working fine, but before it reached 500 hours.
Again: I know this is not a proper research, but more a quick data collection and from there an best guess Statistics live and die with the information basis and below is how I generated mine:
With the help of Google I found 487 considerable statements for working time before first major repair.
Major repair I called everything that required spare parts which are not available without order / shipping time.
If I use the above mentioned data I would calculate the following:
Printer usage 24/7 gives 8760 hours. Considering the apr. 1800 hours MTBF you have 4.86… let us say 5 machine failures per year.
In other words: Every 2.4 month the printer fails and needs spare parts that you might not have on stock.
From here I am going to be very pessimistic
I am not sure for 3D printers, but for a rule of thumb I would use 20% of new price / year as spare parts.
Considering that delivery times for spare parts can easily be 4 weeks a second printer should be considered to keep business running.
For all that disagree to my numbers: You might be totally right 
All the Best
Frank
I’m not sure how many print hours are on mine… according to Octoprint: 606 min, 823 meters since the beginning of the year. So extrapolating out I’d guess 2000 - 3000 minutes overall the lifetime of the printer.
In the last year and a half of owning the TAZ 5, I’ve replaced:
Very happy with the low maintenance and sturdiness of the machine.
My first taz 5 has around 2500 hrs. PEI has been replaced twice due to bubbles (under warranty) Printhead has been replaced once, and rebuilt by me a few times for plastic parts that broke. Power supply replaced once to new version. Other than that, it’s just material. My second taz 5 was a refurb, and has about 400 hrs on it since the day the taz 6 was released. Between the two if them, I average 500 hrs every 4 months or so now.
What I now do is keep two spare assembled print heads, a full set of print head printed parts, and some spare fans, and an extra PEI sheet.
This is a cool thread. Very interesting to compare usage and things we’ve all replaced/repaired over time.
My experience is similar to the others. I bought my TAZ4 as a refurb from I-T-W.com in April of 2015, so i’m going on 15 months now. I have well over 3000 hours on it. But I now call it a TAZ5 to anyone that asks and it’s partially on it’s way to being a TAZ6 with 12mm X axis rods just installed last weekend.
When I received it, Jamie at I-T-W had already upgraded the bed with PEI. Since then, I have replaced the PEI sheet due to my own scratching etc and some errant swipes across the bed with the nozzle too low in my very early learning stages. But i’ve replaced the adhesive 2 more times (in addition to the time i changed the PEI) due to bubbles forming under the sheet. The bubbles formed slowly from edges in (in my case) and then the constant heat and air caused the 3M adhesive to crystallize. From my perspective, i think that’s just normal wear and tear. Good thing is that you get 6 of the sheets of 3M from Amazon for $16 so it’s not too costly to change out. I’ve got it down to about an hour now that I know what i’m doing. 
Other than that, i’ve upgraded from the original Budaschnozzle toolhead that came with the printer to the V2 Hexagon Single extruder hotend. Since then, i’ve build an additional 3 tool heads that i interchange frequently based on what i want to print. The (Single Budaschnozzle version of Flexistruder, V2 Dual extruder and my newest a 1.75 version of the Hexigon Hotend). I haven’t had any probs with any steppers or any other mechanical parts on the printer. I did have to replace the fan on the external power supply as it started howling. So that’s about it for my experience.
great info thanks everyone, so I assume something like octoprint is the only way to log hours?
There might be a firmware feature that can be enabled when compiling the hex… never really looked into it, since octoprint can do it through a plugin.
ive been printing atleast everyday for nearly 6 months. I estimate that I have between 1500 and 2000 hours on my taz5.
I have two small bubbles on my print bed, that I dont even worry about. I swap nozzle sizes by swapping the entire print head.
I have had 0 failures, most of the print time has been on pla about a 3rd in abs and about 5% in petg.