With a lathe, there will ,be all sorts of things that you can do.
Things that break / wear can be replaced, strengthened / modified.
And of course, you can make all sorts of marvelous models and gadgets.
Once you have had a lathe,you will feel naked if it is out of commission for any reason!
If you ask "What lathe should I buy"? you will receive a vast wide variety of answers, not just size but vintage (old vs new ). Before buying a used machine, do take someone experienced with you to look at it and check it.
You do not want to spend money on a machine that is worn out, or has vital parts missing! Nor, as a newbie, you do want to launch into reconditioning a machine. That could be an expensive short cut to disillusionment.
Fantastic work can be, and is, done on a machine that is 100 years old, but you do not want to become the owner of an expensive big door stop!
Try to decide what you want to do with the lathe, so that you get one that suits your needs. A 21" monster is no good for watch making, any more than a watchmakers lathe for producing a 6" scale Traction Engine.
If in doubt, buy a little larger than you first think. You horizons will expand as you gain experience. You can do small work on a big lathe but probably not the other way round!.
As you progress, you will build up a collection of tools, possibly a bench grinder will be an early addition.
As you gain experience, you can make some tools, (such as a Tap Wrench ) which will add to your store of skills.
Suggested books:
L H Sparey "The Amateur's Lathe"
Ian Bradley "The Amateur's Workshop"
Tubal Cain "The Model Engineers Handbook"
They will make good reading while we are locked down, and for many years afterwards.
My suggestion would be to start by using High Speed Tools in the lathe. and learning how to grind them.
Then, my favourite is a Tangential Turning Tool. The toolbit is easy to sharpen, since only one face needs to be ground. You can buy or make. At least two designs have been published in M E W over the recent years.
On another hobby horse of mine, is to make a Centre Height Gauge. Unless the cutting edge is on centre height, it will not cut properly, and will leave a pip in the middle when you face across the end of a bar.
Almost essential with a Tangential tool. Saves SO much messing about!
Make haste SLOWLY, but don't be afraid to seek advice and help.
Find a Model Engineering Club to join for when things return to something approaching normal.
If it is any help, the North London Society of Model Engineers meets in Finchley, and they have a site at London Colney for their track.
Sorry to have gone on at such length!
H T H
Howard