Mortgage Relief -7rys only?

Just bought our first house, myself and husband, both working. Mortgage is 340,000 over 39yrs. What exactly do we get off the mortgage each month? Also does mortgage relief just last for 7years and then that is it for the rest of your life, even if you move again.
Thanks

As married first time buyers you get relief on a maximum of €20K interest per annum at standard rate (20%). This means a maximum of €20K @ 20% / 12 months = €333.33 of your normal repayment each month. This level of relief applies for 7 years from your first mortgage (even if you move/trade up etc.). After 7 years the ceiling for relief is lower and you get this relief for as long as you are paying interest on any loans used to purchase or renovate your home. See [broken link removed]. To estimate your annual interest bill enter your mortgage amount, start date, term and rate into Karl Jeacle's mortgage calculator and click on the Annual Table button. If your annual interest bill in the first seven years is less than €20K then you get relief on the lower amount actually paid.