Dear Loli,
As a midwife and distributor with Ruti of the Epi-no in Israel, I can tell you that if you birth once with no stitches, then you will 99% of the time not have stitches on any of your other births unless the baby is bigger by more than half a kilo. However, if you did have a few stitches, I would recommend the epi-no again. As far as I know, the time interval of 7 years should not have any influence on the state of your perineum.