I've heard it said many times never get another chinchilla for a chinchilla but if you get another one do it for you. After putting two pets together myself I think that is very good advice. There are many reasons to have one instead of two and always be prepared to house them separately if something goes wrong. The potential is always there. For me I like having two and I enjoy seeing them interact and the added variety but they don't always like each other.
I do recommend putting the cages side by side (at least 2" apart) and letting them get used to each other for about two weeks, and then see if they'll play together (perhaps in the bathtub, put their dust bath bin in there) and get along. If they get along without attacking each other and tearing each fur out (or worse) then take the next step, otherwise keep them separate for another week and try again. After a month or two if they don't combine then keep them separate permanently as they most likely never will.
If everything goes well the next step is to clean the cage you want to combine them into thoroughly, replace the shelving and wood if possible with unused wood, and try to make the scent as neutral as possible before putting them together. Don't forget to quarantine your new chinchilla if possible for at least two weeks before putting them into the same room. Keep them in separate rooms for those two weeks and this is also good to accommodate your new pet to its new surroundings. Then keep them side by side for two weeks to start the introduction process and make sure to interact with both of them frequently during this time.
