How long is manageable in a long distance relationship with no visits?

Hiya, I (F21) have just recently gone on an OE and my boyfriend (M21) of 2.5yrs and I broke up because of this (we both felt like long distance could be unfair on each other). I have however found myself sending him things and calling him when I have the chance and am considering proposing we get back together.

I left mid October and am currently looking at going home late July so this will be 9 maybe 10 months apart but we won’t be able to visit in this time. The flight is 24+ hours and he’s never left the country so I haven’t considered this plus he’s a student with a busy degree so it definitely doesn’t seem fair.

Is 9-10 months a reasonable timeframe without any contact? I really would love for us to work and trusting the process while we’re apart makes me anxious.