Perennial (adjective)

1. Lasting for several years; perennial plants live for more than two years.
2. Recurring year after year; perennial problems keep coming back.
3. Everlasting, enduring; perennial love lasts a lifetime.

Origin:

From the latin perennis "lasting throughout the year", from per- "through" + annus "year".

Examples:

1. The perennial flowers came back every year.
2. The perennial stream never dried up.
3. Perennial weeds were hard to eradicate.
4. The perennial debate on tax reform continues.
5. Perennial favorites are always in demand.