I have been 3D printing since COVID. Like many others, I decided I needed a new hobby to spend my time at home on. Shame it was still tied to computers, but it was sufficiently different to distract me. The printer I chose was an Ender 5 pro. I've not linked to it, as it has now been superseded but you may be able to pick one up for a song on ebay.
The printer itself is fairly basic and is shaped like a cube. I, personally, don't like the Ender 3 style of slinging the bed around. Why make the job of bed adhesion so much more difficult by actually moving the model? It can be kind of limiting if you are the type who always wants faster prints. At some point, that print is going to come flying off....
I'm not saying the Ender 5 is the best printer ever, but I do like it. It isn't perfect and that has forced me to put in place some quality of life improvements. These aren't necessarily "mods" although some definitely are. On a newer printer, some of these may not be necessary.
First off, Octoprint running on a raspberry pi. I got hold of the PI4 right at the start of lockdown, before the shortages started. At time of writing, those shortages have only just started to resolve themselves properly and the PI5 has just been announced. While other hardware can run Octoprint, you are going to want a good base in case you decide that klipper is actually the way to go. For me, Octoprint brings several useful features including time lapses, remote viewing and power control, job storage and automatic shutoff. The platform itself does more, and I'll actually discuss this further when I talk about some other changes I did, as they wouldn't have been possible without octoprint.
The next change to the printer I made was in the form of printed parts. I am going to mention a few here and treat them as one. The bracers for the bed were a good shout (I have a second Z-Axis planned, but not installed). I also printed out strain relief for the bed as well as a protector for the wires coming out of the main box. A tool holder is in valuable, as is a control panel protector. The last things I printed were a camera holder (for those time lapses and remote monitoring) and a set of light bars (which I can't find at the moment. I'll update here if that changes). The light bars house LEDs, which I can control with octoprint. There are some pre-set routines, like the colours change from blue to red on heat up and cool down. They also provide an even lighting source for those time lapses.
A BL Touch and extras was a nice addition to replace the switch for bed levelling. Once all of these were complete, I had to reflash the firmware. The firmware that shipped from creality had a few issues, as well as needing to add the BL Touch. It was using Marlin version 1, and I updated to a later version of the same strain. Version 2 was in it's infancy and I didn't have a 32bit board to take advantage of many of the cool new features. I did actually buy a board, but I haven't fitted it yet.
The next things I added to the mix were all about fire safety. Well, mostly. I added a power socket (a sonoff S20) which can be switched on / off remotely. The sonoff is a bit old these days and you may be able to find one which can measure current usage as well. For preference, I would make sure that these devices work locally (i.e. ZigBee or tasmota), so you aren't reliant on the internet.
I also bought a creality enclosure and a smoke alarm. The smoke alarm transmits on 433mhz when it goes off. It is also bloody loud. The signal is received by my Sonoff RF. The Sonoff RF then tells MQTT, which in turn tells Home assistant to message me and kill the power.
The last upgrade to the printer was one of necessity. I want to be able to print almost any filament, so I changed my hotend to all metal. In hindsight, using a cheap one was probably not a good idea. I did use one which was a copy of the original hotend, but the throat was changed over. I had so many clogs, I literally gave up on printing for over a year. During this time, I bought myself a Phaetus dragonfly BMS. This hotend was easily installed in 1 night and has restarted me 3d printing. If you want to know more about that, I have previously wrote about why I fitted the new hotend.
Am I finished with upgrading the Ender 5? Well, no. But I'm also not in a rush to change a load of things either. The printer is working and working well, so why change it? Well, when those struts break I'd rather add a second Z-Axis. To add the second Z-Axis, I'm going to need to move the electronics box. This is not going to be a quick job. Once complete, I'll need to make sure that the printer is all back up and running and nicely dialled in.
After that, I have the new motherboard to consider putting it. This is a straightforward drop in replacement, but it does require a firmware build and making sure your printer is back to where you want it before moving on to anything else.
The last change that I'd like to do is add the tool changer (X-Change) that I got from Kickstarter and Printer mods. Of course, to use this, you need a certain firmware on the printer board, that really needs to be done after the upgrade of the main board.
There will be other changes I want to make, but those can wait.