Out of season, sponges are normally pulled at 12 days. If the ewes are cycling naturally then pulling at 14 days will mean you don’t get the odd one, that maybe naturally cycling already, cycling out of synch.
In 30 years of sponging ewes, I’ve very rarely left them in for 14 days, apart from where I’ve wanted to have big mobs of ewes cycling in two groups, 4 days apart, in order to spread lambing more.
Incidentally, I’m reliably informed that for ewes that aren’t naturally cycling, you can pull a CIDR after 6 days (then disinfect and reuse if you wish) and the ewes will respond ok. I tried it with a small group of late weaned ewes once and they certainly responded.