faberic wrote:So, with an I-roast 2 for example, can I improve my coffee with a little practice?
Probably not with
a little practice but maybe with
a lot of practice. To an extent depends on the quality of you local roaster. Quality of greens you roast will also be a factor. Not all greens by the same name (varietal etc.) are close to equal. Are you a good cook? Turning beans brown is easy, getting the very best from the bean extremely difficult and time consuming taking years of practice, or maybe a lifetime. Coffee is extremely complex and what's best roast for one bean one crop picking/processing etc. may not be even be best for the same dang bean next year or even same year different lot! OTH getting very good results is quite possible. But it won't be by just push the button and let the I-Roast do it's thing.
And is the coffee ALWAYS improved by home-roasting in general?
Absolutely not. There are many excellent Artisan roasters roasting high quality greens with superb results. Can an experienced serious home roaster who can control their roast profile match their results, IMO sometimes yes sometimes no. And I say this as a 99% home roaster for home consumption 6+ years.
The price of an I-roast 2 is the maximum I want to spend, so, is it worth the money and time, compared to the fresh coffee from the local coffee store which is just good enough for me, but from which I don't learn much about taste and coffee?
Who can say if it will be worth the money, and just as or more importantly the time and effort, to you. For me home roasting is enjoyable and rewarding beyond just the cup. There is much to be learned about the bean home roasting. I love the different smells of the roast through it's progression. Sometimes the smell of 1st crack progressing is about enough to make me swoon.

But I'm also an avid hobby chef and enjoy many forms and styles of cooking. If you're a microwave kind of "cook" you probably won't find home roasting for you.
And the last thing I'd like to know: How long can I use the I-roast 2, I don't want it to be broken after a year or two.
Nobody wants their toys (tools) to break!

But they come with a 1 year warranty not 5 or 10 year warranty for a reason IMO. A multiple thousand dollar commercial roaster I'd expect to last a lifetime, multiple lifetimes even with proper maintenance, but not a sub $200 home roaster much akin to a popcorn popper. Could they be made much more durable? Sure, for a much higher price.