I got to Plat 4 last season by maining Udyr, but even then I didn't know when I should be grouping or split pushing.

These are the following reasons I would do either strat:

Grouping:

We're already ahead, push objectives and towers together

Team needs peel for ADC/Mid or just the bear CC

I might be behind and it's better to group since I can't 1v1 whoever comes for me (not USUALLY the case)

Split Push:

When I'm super ahead and can 1v1 anyone, thus causing at least 2 people to come for me

When team is already fighting so I just go ahead and push

To alleviate pressure around the map so we can get objectives

The main problem with split pushing I've noticed is that even though I tell my team I will split, they manage to get caught or engage the enemy team before I'm at their tower and can do anything significant.

I feel like splitting is pretty high risk high reward, just because it requires a lot more teamwork than just simply grouping.

Any advice would be quite helpful :D