I think it's a matter on how much time and energy (not to mention money) you have. When I got Zada she went everywhere with me, even places where she wasn't supposed to go. (like PANAMA69 said, "thank goodness for strollers").
Things were really simple and easy. Then like you, I felt she needed a best "bud", so we got her first cousin Azrael.
I wasn't aware that the running around with two would be just a bit more work, but I soon learned to handle things with no problems. Bath and grooming time was a bit more work and so on. I thought that would be IT till I saw my baby Razael's picture on YT and that was it. I do not in any way regret getting her, but I do feel guilty that all three don't get to go with me as much as just having one or two. Fact is, I don't take all three shopping without my husband along. Reason being, I'm afraid they may all three get dog napped at once since the temptation would be big money signs in a thief's eyes, and next, they are too cramped in the stroller and I haven't found one that's big enough to keep them from being too cramped in. Soooo, now I usually take the baby when I go because she's the youngest and needs all the socializing she can get, just like I did with Zada and Azrael. It works great with three, but it takes some different adjustments for everyone. I dearly love my little pack of three!!!