After repotting my first Semp haul, I started thinking.... Should I try and purchase two of each variety (if $$$ allows)? I have very little experience (read: None) with succulents so I am not sure which varieties are full grown or which will get bigger. Some of them look a little lonely in their four inch pots.

Jamila, since you are buying them this spring, the next few seasons will reveal their growth rate and size and number of offsets if any. You may be surprised at how fast some grow out of their 4 inch homes and you need to put them into bigger. I would say if there's any that you especially like to look at or is a favorite, by all means the more the merrier. But if you are just starting out, you may want to generally feel them out in terms of growth and care and satisfaction.

And of course, they don't have to be singularly in pots. They could be a grouping until they get too much for the pot and then they can be separated. If you are concerned about them getting mixed up, keep the tags with them in whichever pot you plant them in and to make sure you can tell them apart you might consider putting the most contrasting ones next to each other. That way, when they happen to grow into each other you can still see the differences so to separate them correctly to keep ID. I'm big on container plantings for my succulents, but here's a couple of my semp ones:

Great advice Bev. That last container is certainly colorful - nice!

Jamila, I think you'll find that sempervivum grow and reproduce pretty quickly compared to lots of other succulents. By only getting one of each you'll have more room to try out more varieties. Like Bev said, you'll want to keep name tags with them. At first it doesn't seem important, but when you start to trade or purchase more, you'll want to know the names.

Hope you have plenty of space! I bought about 12 different kinds and wish I hadnt now. Just one of my Semps put out 16 offsets already. I've given away a bunch more and this is my first season growing them.