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It's really only something you can judge, if their behaviour is worrying you then it may be time to separate them, they will be maturing now & the cage is probably too big for a pair as more space gives them more opportunity to stake a claim over areas & become territorial.
Pairs can live happily together but some will fall out, it's really up to you whether you feel it's safe to wait & see if things get worse or if you want to separate them now, personally I would generally say it's better to separate too soon rather than wait until one is injured & fights can escalate quite quickly.
People who do keep pairs successfully do seem to agree that it's better to give them less rather than more to minimise fights over things, if you would rather see your hams in a large cage with lots of enrichment, toys etc then you may well do better to keep them individually.