Er....I am a bfc and I wouldn't state any age like that, ILikeToMoveIt
There are no rules. There is no reason to express ever, in fact, unless you want to (or need to for a baby unable to feed direct). It's certainly not necessary for fathers to bond...it's the quality of the interaction between adult and baby that aids the bonding, not the moving of nutrients into the baby, and the interaction can be bathing, nappy changing, holding, cuddling and so on.
Gina Ford's advice on expressing is totally non-evidence-based.
Having said that - you can express at any time of day, at any age of the baby, if you want to. Bear in mind that expressing should not ever mean you later go hours and hours without feeding, as this will impact on your supply...less of a concern with an older, more established bf relationship when things are more flexible. Mothers also need to know that it is a hassle to express (or can be) and prepare the bottle and so on...there is usually enough to do with a new baby without intro'ing another job.
Babies are less likely to reject the breast in favour of the bottle if bf is going well, too.
Main thing to remember is that it is optional to express - where's this talk of 'having to do it' come from?? And that fathers really, really don't need to feed a bottle to bond (plenty of dads don't do this, and would resent a suggestion that this meant they were less bonded!).
Hope this helps.