I run Octoprint on my Ender, and have been saving my uploaded gcode files. The general idea was that if I needed to reprint something, I could click the name, and boom...it prints. Over time, I've found this to not be as simple as previously assumed. It seems that, in my experience, filament flow rates and calibration settings tend to differ from time to time, from batch to batch. What printed great on a spool a few months ago, might not print correctly with my current filament. For a while, I would save each gcode file with a description of the specific filament type, brand, and color. But I've even noticed that this doesn't seem to be 100%. There could be a lot of causes for this (ambient temp/humidity, filament batch, other varibles with the machine, etc.), but in the end, it just seems like reusing gcode after some time typically prints less than stellar.

Does anyone else save gcode files, or is it more common to simply reslice as needed?

Because it isn't a lot of drive space I save the geode files.  I like to have my successful print setups backed up.  "Just in case"

As do I. But I've found that a successful print today, might not be successful down the road.

Yes, I save gcode files. I also save build plates so I can tweak as needed from that gcode output.

Sometimes I just modify gcode directly. Depends on what change is needed.

Filament has generally gotten more consistent and I almost always buy the same brand so yes I do save builds to be recalled at a later date but I also keep the STL with those files so if I want to run a different material or on a different printer I am not fumbling for the CAD data.

In the office this process also works  well when I am remote and want to have one of the guys put a build file. We print parts for light production use and those are not meant to be altered.

I really need a 3d printer. Every time I think about buying one, something much faster and better comes out so I have been waiting on tech/price to level out lol.

Not sure if 3d printers work this way but when I save gcode for cnc I make sure to make a note or screenshot of where zero is.

Gcode is printer-specific. You can't print a gcode sliced for an Ender and Run it on a Prusa, so example.

Thanks! It is like a dark art to me. I am fascinated by it.

The time to get one is now BTW.

Get a P1S or X1C based on your level of buy once cry once mentality and enjoy.

I've never had that much trouble with variations between filament batches.  I only use hatchbox brand, and its consistent.  
I can pull up a file I saved 7yr ago and it still prints fine.

The only time I reslice a model is when I actually want to change something.  The support, or add more items to the build plate, or the layer height.  If none of the settings change, then I print the exact same gcode.

I never save gcode files. Only solid models. I can always re-slice.

Same here.

this

i can never remember all the details of what the slice was - even for a part i make somewhat frequently like an AR trigger guard, things change over time, filament preferences - even filament temperature recommendations or my own preferences within the same brand.  just seems easier to re-slice when ready to do it again