First of all have a good read through your policy (if you haven't got a copy request one). Your excess will be stated in the policy and if you ever make a claim this amount will be deducted from your payout.
I have a single all in one policy that covers me for buildings, contents, employers liability, legal cover, treatment liability and loss of rent etc... In June we had a flash flood of rain and water overspilled from guttering into the flats above the salon through the cavity wallspace. The cost of repairs and renewals came to about £450 and my excess is £300. If I made a claim I would have received £150 net from the insurer.
I spoke to my broker and he estimated that making the claim would add about £70-80 a year to the annual premium for about 5 years, so in the long run I am better off not making a claim.
If you are thinking about making a claim first of all find out your excess. If needed, then also find out future likely (if at all) premiums you will incur in making such a claim. You can then work out if it is financially viable to make a claim on your policy.