Long-running

Continuing for a notably long time, often with sustained participation or interest.

Reach for it when describing duration as an achievement only when the activity remains active or valued

The long-running radio program still invites new poets every week.

• playful

  veteran

  informal praise personifies a familiar program or production

  not when Veteran properly describes an experienced person and can sound gimmicky for an event.

• warm

  enduring

  continued relevance survives changing conditions

  not when Enduring adds resilience or value that simple duration may not warrant.

• professional

  continuing

  the activity remains in progress

  not when Continuing is neutral and provides no sense of unusual longevity.

• professional

  sustained

  effort or attention is maintained without a major break

  not when Sustained may cover a short but intense period.

• formal

  longstanding

  a condition or institution has existed for many years

  not when Longstanding is more static and less natural for a series or performance.

• literary

  perennial

  an event or interest reliably returns

  not when Perennial often means recurring rather than continuously running.

• short-lived
• brief
• discontinued
• one-off

• long-running show

  The long-running show added a relaxed performance for sensory-sensitive audiences.

• long-running dispute

  Mediation finally resolved the long-running dispute over the shared courtyard.

• long-running program

  A long-running program pairs retired builders with young trainees.