ServiceNow Scripting best practices

Follow these to keep code performant and maintainable.

• Query only the fields and rows you need; add setLimit().
• Never run a GlideRecord query inside a loop over another query.
• Use GlideAggregate for counts and sums.
• Centralise reusable logic in Script Includes, not copied business rules.
• Prefer configuration and out-of-the-box features to stay upgrade-safe.
• Guard against recursive business rules.
• Cover critical logic with ATF tests before promoting update sets.