How long does it take to get a patent?

There is no simple answer to this question. But unless you fast-track the application or you fall under special consideration, and assuming it's a utility patent (design patents often go through in a year or even less), then you could be looking at 2-7 years.

Why so long? Well, first your patent sits in a queue until eventually it's designated to be assigned to an Examiner. Then it's assigned to an Examiner. Now you have no idea how many Office Actions you're going to receive or how you're going to respond to them. You might go through a couple and receive a Final Rejection. Of course, you can file an RCE, meaning pay them more money, and they'll look at that again. More time. If the patent takes a really long time and the USPTO under 154(b) determines it qualifies for an extension, then they'll actually extend the life of the patent. The fact that this happens so frequently attests to how long patents can take to be issued.

And all along, your patent, even with revisions, could be rejected. Even after RCEs, you can still file an Appeal. More time.

Also keep in mind that if you do fast-track (and fast-tracking doesn't reduce the number of Office Actions), you have some limitations. A fast-tracked app can have no more than 30 total claims, of which no more than 4 can be independent claims. So if you have a bunch of claims, you may have to file multiple fast-tracks. Right now, I'm working on a very complex patent where a number of initial applications were split into 3, each of which was fast-tracked. However, there was only one PCT, which was the agglomeration of all of the 3 fast-tracked ones. And if you fast-track all your applications, then you have less time to file CONs or CIPs and to keep the family open. For this reason, one strategy is to file multiple fast-tracks and one on the regular track, which will keep the family open for longer.