In the context of it being a hobby here, you can do it however you want, and there are a lot of different reasons using these old computers one way or another.

In the context of it being a hobby here, you can do it however you want, and there are a lot of different reasons using these old computers one way or another. Some like finding out every detail of the hardware, some enjoy the challenge of breaking its known constraints. Depending on the exact situation, an emulator might work or not. I'm currently repairing old HP calculators. All of those can be very accurately emulated even on my iPhone, but I did it for the challenge, for the learning experience, and really because I just like the feel of the keyboard and the unit itself--and the broken ones are much cheaper on eBay. In the cases where an actual need is to be fulfilled, e.g. for business reasons (it happens), if an emulator works it can easily be the best possible way. If hardware is involved (including old disks), again it might not.