I started my printing long back with an Opemus Axiomat II, condensor, for 6x6 to 35mm (took some time to learn how to deal with uneven light for 6x6, but I managed in the end, it was OK for 35mm).
Then I got a more modern one, a LPL C770 MX with colour head for 6x7 and less, and put the Opemus in a wardrobe (where it still is!).
Got into 4x5 and managed to get a DeVere 504 (colour head) - great machine! But also a Durst Laborarator 138 S (condensor (and also spot light)).
Since in fact I could use the Durst for all my formats (save my 8x10 which will go as contact prints) I thougt to get rid of all the others. But I didn't, and I'm glad for that!
It's great, as many now has pointed out in this thread, to have several enlargers going, and thus the possibility to work with several negatives at the same time, and for different negs choosing different enlargers with different kinds of light systems. For a long time I put the LPL in the wardrobe (together with my Opemus), but was Very happy when I saw the possibility of rearranging the darkroom to get it back into my darkroom, made a lot of things easier and saved time.
Most of the time I use the LPL for 6x6 and 35 mm, the DeVere for 4x5 and middle format up to 6x9 (roughly the same type of light system), and the Durst for 5x7 and others that profit from the condensor light. Would be nice to have the coldhead insert for the Durst, but don't know how to get one.
If you have space, have as many enlargers as possible!
BTW, you don't, necessarily, need an enlarger for contact prints (Weston and many other just used a hanging lamp above the contact frame).