How often do you replace seals?

[Mebbid]

I was thinking about this the other day because the equipmebt i have is all HOB rather than in a sump where this would be less of a problem. So question is, how often do you guys replace seals? It stands to reason the older the seals get, the higher the likelihood of failure.

 

[Delapool]

I had a seal on the API canister go after about 3 years I think. The UV light housing was rusted out and I was a bit fed up so when I saw the same canister filter in the shop I just bought it (seal problem solved, albeit expensive - it helped that every $20 spent went into a raffle which picked up $100 in fish food for me but sadly not a new tank).

The other API canister filter has been going about 5 years now with same seals. But I don't pull them apart every month though.