How do you use Script Activities in Automation Studio, and what are best practices for error handling and logging?

A Script Activity in Automation Studio runs SSJS server-side on a schedule or as part of an automation. Best practices:
Error handling: Wrap all logic in try { } catch(e) { } blocks. Log errors to a custom logging DE with fields: timestamp, scriptName, errorMessage, stackTrace.
Logging: Use Platform.Response.Write() sparingly (output is discarded in automation context); instead write log entries to a DE using Platform.Function.InsertDE() or WSProxy.
Idempotency: Check for existing records before inserting to avoid duplicate processing on retry.
Timeouts: Script Activities have a 30-minute limit. Break large batches into smaller automation runs or use Automation Studio loops with filtered DE segments.
Rate limits: Marketing Cloud APIs enforce rate limits (e.g., REST: 2,000 requests/minute). Implement back-off logic in SSJS using Platform.Function.Sleep(milliseconds).