diff --git a/Cargo.toml b/Cargo.toml
index 53e14412..e3dd1ccd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -186,3 +186,6 @@ doc_markdown = "warn"
 manual_midpoint = "warn"
 semicolon_if_nothing_returned = "warn"
 unnecessary_semicolon = "warn"
+
+# nursery lints configuration
+# or_fun_call = "warn" # enable it to help detect non trivial code used in `_or` method
diff --git a/src/api/k2v/router.rs b/src/api/k2v/router.rs
index 4e50bfa6..642b002b 100644
--- a/src/api/k2v/router.rs
+++ b/src/api/k2v/router.rs
@@ -62,7 +62,7 @@ impl Endpoint {
 		let (bucket, partition_key) = path
 			.split_once('/')
 			.map(|(b, p)| (b.to_owned(), p.trim_start_matches('/')))
-			.unwrap_or((path.to_owned(), ""));
+			.unwrap_or_else(|| (path.to_owned(), ""));
 
 		if bucket.is_empty() {
 			return Err(Error::bad_request("Missing bucket name"));
diff --git a/src/api/s3/multipart.rs b/src/api/s3/multipart.rs
index 5e56408f..c5eea912 100644
--- a/src/api/s3/multipart.rs
+++ b/src/api/s3/multipart.rs
@@ -494,7 +494,7 @@ pub async fn handle_complete_multipart_upload(
 			.root_domain
 			.as_ref()
 			.map(|rd| s3_xml::Value(format!("https://{}.{}/{}", bucket_name, rd, key)))
-			.or(Some(s3_xml::Value(format!("/{}/{}", bucket_name, key)))),
+			.or_else(|| Some(s3_xml::Value(format!("/{}/{}", bucket_name, key)))),
 		bucket: s3_xml::Value(bucket_name.to_string()),
 		key: s3_xml::Value(key),
 		etag: s3_xml::Value(format!("\"{}\"", etag)),
diff --git a/src/api/s3/router.rs b/src/api/s3/router.rs
index 3f2d9208..69c95876 100644
--- a/src/api/s3/router.rs
+++ b/src/api/s3/router.rs
@@ -330,7 +330,7 @@ impl Endpoint {
 		} else {
 			path.split_once('/')
 				.map(|(b, p)| (b.to_owned(), p.trim_start_matches('/')))
-				.unwrap_or((path.to_owned(), ""))
+				.unwrap_or_else(|| (path.to_owned(), ""))
 		};
 
 		if *req.method() == Method::OPTIONS {
diff --git a/src/garage/cli/remote/admin_token.rs b/src/garage/cli/remote/admin_token.rs
index 5a0b0595..144c11c7 100644
--- a/src/garage/cli/remote/admin_token.rs
+++ b/src/garage/cli/remote/admin_token.rs
@@ -1,3 +1,5 @@
+use std::borrow::Cow;
+
 use format_table::format_table;
 
 use chrono::Local;
@@ -42,18 +44,18 @@ impl Cli {
 				table_list_abbr(&tok.scope)
 			};
 			let exp = if tok.expired {
-				"expired".to_string()
+				Cow::Borrowed("expired")
 			} else {
 				tok.expiration
-					.map(|x| x.with_timezone(&Local).to_string())
-					.unwrap_or("never".into())
+					.map(|x| x.with_timezone(&Local).to_string().into())
+					.unwrap_or(Cow::Borrowed("never"))
 			};
 			table.push(format!(
 				"{}\t{}\t{}\t{}\t{}",
 				tok.id.as_deref().unwrap_or("-"),
 				tok.created
-					.map(|x| x.with_timezone(&Local).date_naive().to_string())
-					.unwrap_or("-".into()),
+					.map(|x| x.with_timezone(&Local).date_naive().to_string().into())
+					.unwrap_or(Cow::Borrowed("-")),
 				tok.name,
 				exp,
 				scope,
@@ -236,8 +238,8 @@ fn print_token_info(token: &GetAdminTokenInfoResponse) {
 			"Expiration:\t{}",
 			token
 				.expiration
-				.map(|x| x.with_timezone(&Local).to_string())
-				.unwrap_or("never".into())
+				.map(|x| x.with_timezone(&Local).to_string().into())
+				.unwrap_or(Cow::Borrowed("never"))
 		),
 		String::new(),
 	];
diff --git a/src/garage/cli/remote/key.rs b/src/garage/cli/remote/key.rs
index 657607ea..68de358f 100644
--- a/src/garage/cli/remote/key.rs
+++ b/src/garage/cli/remote/key.rs
@@ -1,3 +1,5 @@
+use std::borrow::Cow;
+
 use format_table::format_table;
 
 use chrono::Local;
@@ -33,11 +35,11 @@ impl Cli {
 		let mut table = vec!["ID\tCreated\tName\tExpiration".to_string()];
 		for key in keys.0.iter() {
 			let exp = if key.expired {
-				"expired".to_string()
+				Cow::from("expired")
 			} else {
 				key.expiration
-					.map(|x| x.with_timezone(&Local).to_string())
-					.unwrap_or("never".into())
+					.map(|x| x.with_timezone(&Local).to_string().into())
+					.unwrap_or(Cow::Borrowed("never"))
 			};
 			table.push(format!(
 				"{}\t{}\t{}\t{}",
@@ -288,8 +290,8 @@ fn print_key_info(key: &GetKeyInfoResponse) {
 		format!(
 			"Expiration:\t{}",
 			key.expiration
-				.map(|x| x.with_timezone(&Local).to_string())
-				.unwrap_or("never".into())
+				.map(|x| x.with_timezone(&Local).to_string().into())
+				.unwrap_or(Cow::Borrowed("never"))
 		),
 		String::new(),
 		format!("Can create buckets:\t{}", key.permissions.create_bucket),
diff --git a/src/model/s3/lifecycle_worker.rs b/src/model/s3/lifecycle_worker.rs
index a400b5bf..f014337f 100644
--- a/src/model/s3/lifecycle_worker.rs
+++ b/src/model/s3/lifecycle_worker.rs
@@ -65,7 +65,11 @@ pub fn register_bg_vars(
 	vars: &mut vars::BgVars,
 ) {
 	vars.register_ro(persister, "lifecycle-last-completed", |p| {
-		p.get_with(|x| x.last_completed.clone().unwrap_or("never".to_string()))
+		p.get_with(|x| {
+			x.last_completed
+				.clone()
+				.unwrap_or_else(|| "never".to_string())
+		})
 	});
 }
 
diff --git a/src/rpc/layout/helper.rs b/src/rpc/layout/helper.rs
index 2fa6f913..89ffe2ad 100644
--- a/src/rpc/layout/helper.rs
+++ b/src/rpc/layout/helper.rs
@@ -169,7 +169,7 @@ impl LayoutHelper {
 		Ok(versions
 			.iter()
 			.find(|x| x.version == sync_min)
-			.or(versions.last())
+			.or_else(|| versions.last())
 			.unwrap())
 	}
 
@@ -271,7 +271,7 @@ impl LayoutHelper {
 					.map(|x| x.load(Ordering::Relaxed) == 0)
 					.unwrap_or(true)
 			})
-			.unwrap_or(self.inner().current().version);
+			.unwrap_or_else(|| self.inner().current().version);
 		let changed = self.update(|layout| {
 			layout
 				.update_trackers