Most mainline Insurance companies will allow you at least 2 (or maybe even 3) replacement windscreens (lets alone chip repairs) before considering loading your base premium at renewal. I've worked for General accident (as it used to be) and Norwich Union and that at least used to be the attitude of the claims dept back when I was there.
Had 2 broken windscreens last year on my swift sport and it made not a difference at renewal time. Not that it mattered, as I changed insurer anyway and both were declared and did not effect my NB (IE. New Business) quotes. Though I'm sure some companies may well try and screw you sideways these days.
Technically, a windscreen claim is still accident damage, so "yes" you should always declare them with an Insurance company.