Are you trimming on that schedule just because or another reason?
I'm just curious bc initially I too had a 'trim every 3months schedule' until I realized it really wasn't working for me. Sometimes I would see a raggedy end & be like do I cut or wait it out... however now I only dust on an as needed basis, thats it. If I see my ends looking ruff I dust no matter what time frame has gone by since my last dusting. By doing it this way it saves me the trouble of having to 'cut' bc I eliminated a major split issue before it could even begin.