For length:
* Extended: Describes something that stretches out over a significant distance.
* Prolonged: Implies that something is longer than usual or expected.
* Extensive: Refers to something that covers a wide area or scope.
* Spacious: Describes something that has ample room or space.
* Durable: Means something is designed to last for a long time.
For time:
* Enduring: Something that lasts for a long time and is strong.
* Chronic: Refers to a condition that lasts for a long time.
* Persistent: Means something that continues for a long time, often in spite of difficulties.
* Protracted: Indicates a process or event that lasts for an extended period.
* Eternal: Means lasting forever.
For other contexts:
* Lanky: Describes a person who is tall and thin.
* Slender: Refers to something that is thin and delicate.
* Lengthy: A more formal way to say "long."
* Drawn-out: Describes something that is slow and tedious.
The best adjective for "long" will depend on the specific situation you are describing.