If dried out well and stored properly, they will last for months. Friends of ours had enough garlic to last them from last summer and well into the spring. I think they only had to resort to shop bought for two or three months whilst their next crop ripened.
We have got about 12 heads this year so will probably run out sooner as we use it quite a lot.
The BBC book "Grow your Own Veg" by Carol Klein is wirth a read. It accompanied the series that was on a couple of years ago and goes through the RHS 3m x 3m veg plot which gives you a year round crop if you wanted to expand into other veg. she goes through all the types of veg, when to sow and harvest and which varieties are better etc.
It certainly took the mystery out of it all for me
We're only in our third year, but first proper year with a grown up veg bed and have had great fun. My 6yo DS thinks it's all great stuff, and he'll try our home grown veg where he wouldn't is we bought it from the supermarket....like courgettes and now he eats all kinds of courgette no matter where they came from.
Really? My lo is not fussy atm but I thought it would be something she could 'help' with next year maybe and it may encourage her to try other stuff to. I will have a look at my local library and see if they have that book, would be useful to have something as a starting point as ideally I would like to plant a proper veg garden like my own mum had years ago, I just thought starting small would be a better idea than taking on loads! Thanks for the info LackaDAISYcal