It's great which the Python team is planning on this, and for sure they are far more gifted and skilled than Let me ever be. Still, I would estimate there is a 100% that a person's code somewhere will get rid of working how a want it's meant to when Python is upgraded.
For example, at meteorological offices there exists a lot of operational Fortran code actually for non-speed-essential components, and code stability is one of the reasons. I've heard concern for instability is probably the objects they get against moving for you to SugarCRM consultants (besides language inertia of course; it's only possible for new code not relying on old code). Of course, one strategy with regard to stable code would be to freeze the entire main system. But that seriously isn't always feasible.
Developers have a responsibility to take care of their code. But sometimes, stability is a vital requirement in manufacturing code, and code ought to simply run pertaining to 10 years with the necessity for someone experiencing the code on a yearly basis to adapt the item for language adjustments. Or I will often have small scripts, for example pertaining to scientific data analysis, that I must revisit after certainly not touching them for a long time.
Programming different languages change. Libraries change. Some code from 5, 10, or even two decades ago might however run and generate expected results, whereas some code from year or so might fail using a syntax error. This is to some extent inevitable, since Magento UK evolve (no less than, most do).
This is an unsolved problem in your field. There's no way to make certain that your code will indefinitely work. Even if the code was truly perfect in the forwards-compatible sense (and whether it is, please come help my company!; )), if it goes on, uses, or is employed by any other software which gets the bug or changes at all, your code might not work.
Doing any these things may/will increase how much work you should do. I think which makes sense -- each of these points can also be generated for how to post good go there, which is quite difficult (for me). Sometimes you may need to violate some of those suggestions. That is correctly acceptable, but be aware of the costs.