We have 3 - OCT TERM 1/ March Term 2/ and early July Term 3
Oct: How they're settling in, what they've been rated at for Writing and Maths (they won't give reading levels - I think they're frightened to).
March: How they're getting on so far. Is there any sign of improvement since Oct. Things we really need to focus on for the remainder of the school year.
July: Review of end of school year report. Things to work on over summer.
I think the meetings can be useful, but really depends on how prepared the teacher is and how willing they are to openly discuss your child. Some teachers just prefer the usual patter, lovely to teach, happy child, etc... and don't want to talk nuts and bolts - i.e. 'she can't subtract for toffee and we need you to help her more at home with that.' Other teachers are very matter of fact, '...tries hard but really struggles with writing, I've printed out this leaflet with ideas you might like to try at home.'
I prefer the latter style of teacher, rather than being told everything is lovely when it isn't (but my DDs have had struggles in various areas). It also lends the impression they actually are aware of what my child can and can't do.