So the moral of the story is if its not broke dont fix it hahaha
Yes and No. If your SD is running good, then upgrading stock parts is a matter of opinion (I will continue on this in a second).
Glass bed and enclosure are not stock (yes I know, they do offer an enclosure). These two upgrades will solve a lot of hassles you may not realize are due to temperature changes in the environment. They are also the cheapest and easiest mods to do.
The next up is the MK5 extruder upgrade. Buying a couple of LM8UU and printing out the parts is relatively cheap, and considering the rate at which the acrylic fails, is an eventual process for all SD owners. That brings it to second place.
The rest of the mods are all a matter of effort vs payback. All of those mods are not generally needed if your printer is running well. They are also subjective. Maybe you have Z wobble banding, maybe you dont. Maybe you dont care. Do you print extreme detail models, or do you print structural pieces for a hobby? The payback is determined by the individual user. But in the end, if you have been running for a few months already without already being unhappy about a specific flaw in your prints, you wouldnt have asked this question. If that is the case, then these upgrades are secondary at best.
Chuck Bittner is a quadriplegic gamer who is petitioning the major console developers to include internal button remapping in all console games. You can help.
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