Most frags give 5-10, I would advise farming Kabuto Frags from Survival trial and Hinata from Elite instance to maximize the amount of extra frags you get as both of them give 10 refinement points each. Character fragments also give 10 so collecting froggies can help I recently got 4* Iruka for free just doing this

Here's what it looks like assuming you're getting extra frags every day

Iruka 2* - 9000 Refinement Points - 900 Extra Frags - 45 days

Iruka 3* - 15000 Refinement Points - 1500 Extra Frags - 75 days

Iruka 4* - 30000 Refinement Points - 3000 Extra Frags - 150 days

Iruka 5* - 60000 Refinement Points - 6000 Extra Frags - 300 days

Total: 114000 Refinement Points - 14000 Extra frags - 570 days (Roughly 1 and a half years)