diff --git a/README.md b/README.md
index 5023cf35a..55f9c7a67 100644
--- a/README.md
+++ b/README.md
@@ -545,6 +545,15 @@ We're using the `Cache.file` method, that can also be given a `Logger` (for more
 
 ## Extra features
 
+### TTL
+
+Changing things in cache are given a time-to-live (TTL) of **24 hours** by default. Changing things are artifacts for versions ending with `-SNAPSHOT`, Maven metadata files listing available versions, etc.
+
+The most straightforward way of changing that consists in setting `COURSIER_TTL` in the environment. It's parsed with `scala.concurrent.duration.Duration`, so that things like `24 hours`, `5 min`, `10s`, or `0s`, are fine, and it accepts infinity (`Inf`) as a duration.
+
+
+
+
 ### Printing trees
 
 E.g. to print the dependency tree of `io.circe:circe-core:0.4.1`,
diff --git a/doc/README.md b/doc/README.md
index 4e28f0b94..3ebdb034b 100644
--- a/doc/README.md
+++ b/doc/README.md
@@ -572,6 +572,22 @@ We're using the `Cache.file` method, that can also be given a `Logger` (for more
 
 ## Extra features
 
+### TTL
+
+Changing things in cache are given a time-to-live (TTL) of **24 hours** by default. Changing things are artifacts for versions ending with `-SNAPSHOT`, Maven metadata files listing available versions, etc.
+
+The most straightforward way of changing that consists in setting `COURSIER_TTL` in the environment. It's parsed with `scala.concurrent.duration.Duration`, so that things like `24 hours`, `5 min`, `10s`, or `0s`, are fine, and it accepts infinity (`Inf`) as a duration.
+
+```tut:invisible
+import scala.concurrent.duration.Duration
+
+Duration("24 hours")
+Duration("5 min")
+Duration("10s")
+Duration("0s")
+Duration("Inf")
+```
+
 ### Printing trees
 
 E.g. to print the dependency tree of `io.circe:circe-core:0.4.1`,