Test U's half life is really nice for people who want to do less frequent injections, but you'd still want to do it once a week to have overlapping doses. The main drawback is that the concentration tends to be about the same from most pharmacies, meaning that you're going to have to inject larger volumes and your areas of injection may be limited. You will also have higher highs & lower lows than more frequent injections.

That said, it's still fine to use as long as you understand that. I've certainly used it before when going on a week or two long trip where I didn't want the hassle of bringing my vials/injection supplies. It didn't feel as great but it was certainly still working.

Like you say, it is harder to get an Rx for because the pharmacies that service TRT industries don't often produce it. They don't because it's not quite as good for treatment and thus the demand just isn't there, they always follow the money for what they focus on providing. It kinda sucks, but if we're to see better options for this then it will need to be driven by demand.

For long term patients, generally no. Most people settle on a dose and after the initial dialing-in they sit quite happily without much issue.