[villagetinker]

Originally Posted by budforlife

looking for recommendations for new concrete landscape curbing install, or alternate edging type that would last 15 to 20 years

IMHO, your 15 to 20 year requirement is not practical, unless you are putting in a full foundation (think curbing along a road). Any landscaping type curbing or walls is subject to root growth, ground settlement, etc. Further, there is on going maintenance, both require some form of yearly cleaning, and possibly sealing to slow mold growth.
The only thing I have seen actually last that long is a LOOSE stone wall (aka stacked stone, NOT the landscaping stone) as these can move a little and not look out of alignment.
I wish you a lot of luck with your project.