The beauty of doing your own maintenance work is that if something happens out on the road (a) you have no-one to blame but yourself but (b) more importantly, you will know what the problem is and how to fix it. Which also means you will have a toolkit that is capable of fixing most things. About the only thing I can think of that my on-road tool kit wouldn't be able to fix would be removing a cartridge bottom bracket, and I should know the condition of that before I depart anyway.

Yes, time is a factor, and if you are working two jobs, then that might be limited. I have heard Americans say so many times that if your job value is so high and so important, that you should pay someone else to do the bicycle work for you... but three weeks is a hell of a lot of lost time (and then you can convert that to money value) when you could have ordered the stuff off the internet, spent a couple of hours on a couple of nights a week and done the rebuild yourself. And learned something of value to you as a cyclist.