1998 Honda Accord questions

Hello,
This is my first post here. I am receiving my used 1998 Accord at the end of the week from a local Honda dealer. It is an LX with the 2.3L L4 SMPI VTEC OHC engine with 66,000 miles on it. This car is a "certified" Honda used car that[as far as I understand it] has three more years warranty on the powertrain and one year on every thing else. My question is : should I, in addition, take out a warrantybynet for $900 for 2yrs concurrent and beyond the dealers warranty? Are these warrantees all they are cracked up to be? The price for the car is $11,495. Also at what mileage should the timing belt be changed? Thanks.
R.Q.