Mac Mini 4 suggested set up and cost

Likely completely unnecessary configuration of the user is a typical user that does:

• Web Surfing
• Email
• Basic tasks such as spreadsheets and word processing.

If the OP is media professional then your suggestions are valid.

For the above basic tasks an entry level or mid tier with 16GB of RAM and a 1 TB SSD they will have a very nice machine that will be good for years to come. Again, a Studio Display is likely a waste too. There are multiple 4K displays of various sizes that are substantially less money that are all excellent.

Get the basic model at £599.

The only "problem" is the tiny SSD so buy a 1 TB Crucial SSD and USB 3.0 enclosure (other makes are available!) for around £60.

You will need a mouse and keyboard but you can use your iMac's. If not, any cheap mouse and keyboard will work (£20).

You can get a 27" 1080p monitor for just over £100 or 4K for £220.

The cheap Logitech 270 webcam (under £20) is very good.

So if you have to buy everything you are looking at £800 or just over £900 for 4K.

You can plug the mini into any modern TV via HDMI and do away with a monitor if you wish.

That's the advantage of the mini, if the monitor fails you just get another or use a TV. With the iMac, if anything fails the whole computer is out of business!

Incidentally the cheapest M4 mini has a more powerful processor than the cheapest iMac and far more connection ports.

Setup is pretty simple. Simply connect the old iMacs keyboard and mouse to the new computer and select an external monitor (there are hundreds to choose from), prices for these start at <$100 however for a nice one expect about $300. I would connect using a HDMI connection. Then follow the directions below:

·       Always connect your old Mac's Time Machine External Hard Disk prior to startup, this will allow a migration from your TM backup and it will be dead simple! When you start the new Mac for the first time it will startup Setup Assistant (SA), SA will get to a point where it asks if you are migrating from another computer, select Yes and follow the on-screen prompts and it's done! It is that simple! This is the easiest, quickest and most reliable method to migrate from the old Mac to the new Mac is to simply connect the old Mac's Time Machine External Hard Disk to the new Mac using a USB cable before you turn on the new Mac. 

·       NOTE 1: You will likely need a USB A to USB C adapter, you can find them on Amazon for $10 or less.

·       NOTE 2: If you have already done SA on the new computer then simply connect the Time Machine External Hard Disk using a USB cable and launch Migration Assistant (MA) which is located in Applications - Utilities - MA. Then follow the on-screen prompts.

·       The ONLY difference between MA and SA is MA will create a new user account that you need to log into.

Both SA and MA migrate applications (not 32 bit apps), data files & settings. They do not migrate Mac OS itself. Some professional apps such as Adobe and Microsoft apps may require re-installing their apps as they will not allow them to be migrated. As long as you kept the security keys for installing their apps, it is not an issue. 

Finally, never EVER use Wi-Fi when doing Setup Assistant or Migration Assistant. Why, it simply fails in most cases. Please read and follow the directions in Setup Assistant and Migration Assistant. If you do not have a Time Machine backup of the older Mac then create one! If you are not aware of Time Machine, please read Back up your Mac with Time Machine and finally if you need an External Hard Disk to use as a Time Machine External Hard Disk then many experience users on these forums prefer the OWC Mercury Elite Pro due to it's reasonable price, high level of quality and ease of use. 

Personally I would get no less than 1 TB but that is because I tend to store a lot. The amount of storage one needs is very personal. The best gauge is to look at the old Mac and see how much storage they used in the past. Unless their habits change dramatically (up or down) get roughly the same amount or more.

Agreed that 1tb is bare minimum. I have 2 tb on a 2018 (doing music prod and some video) and that way can keep stuff alive for longer before moving to external storage once done.

agreed that for typical user (word processing, web surfing, ….) 1 tb can be overkill, but if budget balance is also needed, don’t overlook more ram depending on what you do.

Your iMac is still very young and although the M4 mini will be faster, it will only be in the order of 50% quicker which is not exactly eye-watering.

Assuming the iMac is fulfilling all your needs I would advise you to hang onto it for at least a couple more years by which time there will probably be an M5 or higher available with far more performance.

Go for M4 Pro with 24GB RAM and 1 TB of SSD storage.

You can use your Magic accessories from your iMac.

For monitor you can choose a Studio Display or another brand.

4K Monitors

No idea what used iMacs fetch.

1080p monitors are perfectly usable. I have one together with my 27" 5K iMac. If you compare them side by side the iMac is definitely better but once you start using the 1080p you quickly forget the difference.

Check the Apple Store online Buy Mac - Apple, or better, visit one in your area.

Yeah, that's true. It depends on use, but at least I will go for 512 GB, 256 is just for surfing, but for more complex tasks 512 will be better.

It is, you need to assess what your needs are based on past and projected needs.