A Design Element Typically Forgotten (Plant Utility)
First, I appreciate everything all of you designers and landscape aficionados do for this forum - all free of charge, on your own time. However, something I think we all forget sometimes when landscaping is we want to look at the "final" 25, 40, or 60 year size of plants is that realistically, most of us will either be long dead when they reach that size or certainly moved away. While the future homeowners may appreciate it, more realistically they will neglect and kill/let run wild all the landscaping anyway.
So my point that I believe is forgotten and needs to be considered is to think about what plants will serve your needs for 5, 10 or 15 years without necessarily regarding the the 25 or 30 year plant size. "Utilize" the plant for 10 years, then cut it down and replace it if it's too big. In my opinion, that's better than selecting (and waiting...) for the "right size" 25 year old plant to mature especially when I will likely move or kick-the-bucket after maybe 10. So I planted something that never served it's purpose for me and future owners may or may not fully appreciate.
Now I am not saying to not think long-term and have a 25 year plan. But don't let the 25 or 30 year plan get in the way of your needs in 5 or 10 years because likely you won't be around to enjoy it.