Nothing stays permanently, even a building will wear off as time passes, it doesn't stay the same. Knowing nothing stays the same, it actually gives us hope. We may have failed, we may be in a difficult situation, we may feel down, but we should still feel hopeful because nothing stays the same. But it is important that we work hard, transform ourselves to make things better.
Our sufferings come from our ignorance thinking that things stay the same forever. Therefore, when things change, we are not happy, we are upset. We have to learn to accept nothing stays the same forever. But it does not mean we don't have to be sincere with people.
Knowing that things do not stay the same, we also accept that death can come to us at any time. When we die, we cannot bring anything with us except our karma. Therefore, when we have found a guru, we should make use of the opportunity to purify as much karma as possible and also to collect merits.