Flights - depends on whether you are going at peak time or not.
People say that if you want peak school holidays you need to book on the day that are released, but I can't help wondering if the airlines exploit the initial panic and put the prices up, before dropping later.
If not peak time, they go up and down, and if a flight isn't selling well, they'll drop the prices later to encourage bookings. It's also good if you have flexibility as you can go at different times based on when flights are cheapest. We usually book somewhere between one to 3 months and sometimes tailor exact date/destination based on cheap flights along with other factors.
If I was looking at 14 months away, I wouldn't even be thinking about booking that far ahead, and would only book that far ahead if I had to go to that place on those days and there was a risk of things selling out or getting really expensive and in those circumstances I wouldn't expect to get the best price, if I did it would be a bonus.
It's good to have a basic idea of what a flight costs on average, a target price if you will. After all, the cost of the flight is often a minor component of the cost of a holiday, so it's not worth worrying about the odd £50 here or there. We usually pay around £100 pp for a return flight to the Med, without luggage, so if it's less than £100 it's cheap, and if it's much more than £100, it's starting to look expensive.
Car hire is less of a rush unless you need something very specialised that will sell out. Also consider all the pitfalls that are likely to rip you off.
But for both, pay by credit card if you are booking so far in advance, so you are protected if the supplier goes bust (this happened to us with Monarch and we got all the money back including consequential losses (extra expense of more expensive short notice flights) from the credit card company - your travel insurance is unlikely to cover this unless you have already done your outward journey).