Forward Kinematics or Inverse Kinematics ? Which to choose for a robot?

Hi everyone!

Let's say I would like to build three types of robots:

1. Hexapod/Spider

2. Humanoid

3. Drone

Would you say that IK is a must for all these types of robots or FK is enough ?

I am not planning anything complex, at least not for now. So, if hexapod or a humanoid can walk (with a more or less natural gait), maybe jump or punch/kick, I'd be more than happy. I do not want them to do any acrobatics.

I do know that the most complex and the smoothest robots are built using IK. I am just wondering if FK is enough for an "average" robot ? I imagine it will take some trial-and-error to fine tune a robot with FK.

The reason I am asking is because I know how to calculate and apply FK and I am contemplating if I should invest time and effort into figuring out the IK or it's not worth it in my case.

I hope I was able to communicate my thoughts well.

Thanks in advance for any comments.