Load testing should never be considered as a one-off process. Even when testing is confined to a specific pre-peak period, retests are essential to ensure that your changes have been successful.
The best approach is regular load testing, with increased frequency in the run-up to code lockdown. Best practice involves testing after making changes to improve performance to understand how your improvements are working or how they’ve affected the performance of other components.
Sticking to this process can save time and money in the long run as it’s easier to manage and enables smaller changes at each stage whilst ensuring each change is verified before moving on to the next stage.