Kickboxing Tkd

what is the best long-term planning approach to learning martial arts?
i would like to train in different arts– i.e. jujitsu and a stand-up hard style, to be well rounded..
but i’ve heard it’s good to have one primary art that you train intensely in for several years, and then add on others (so as not to be so-so in many, not great at any). with this reasoning, i’d want to train 5 years a striking style (or what’s fun to me), and later supplement with jujitsu for groundwork. do you agree? or is it okay to start several at once?
i’ve also heard that those who train primarily in styles like kickboxing, who later add in Wing Chun or taichi, find their skills in their original art improves dramatically.
..for me, something like taichi would be great spiritually and as a supplement, but not primary given my love for high intensity
my motivation — spirituality, as an art, as a sport, some practicality
my natural ability- striking, agility, flexibility.. i’m 5′4″ light and quick
past experience – tkd, no ground fighting at all
any ideas?
If you are learning a Martial Art in two different areas that don’t overlap you should have no problem learning both at the same time.
In other words you can learn a striking art like Kickboxing or Karate and a grappling art like BJJ at the same time because they don’t overlap. But when you try to learn more than one MA in the same area you could run into problems. For example, if you learn TKD and JKD at the same time, you will have some conflicts in techniques. I would not recommend doing two striking arts at the same time.