If the strings are very old I would replace them as well. I generally change strings every few months, generally every 3-6 months. Bridges on the other hand last a very long time and unless a bridge is warped, cracked, or completely broken, or not fitted right from the git go,or is a poor quality bridge, there is usually no need to replace it. I know players who have been using the same bridge for decades or who have never changed the bridge since they owned a particular violin.  Strings however do tend to change with age and I do notice a difference when I replace a relatively old string with a new one of the same brand and type. 

I change my strings every six months or so. I keep the old ones as spares. If your strings are old by all means change them.