When is this a problem?
When a new line item is created, a summary method is added by default. Many line items do not need summary calculations.
Why is this a problem?
Running unnecessary calculations can increase the time it takes to open a model.
How to correct:
When creating a new line item, make it a habit to turn off summarizing. If a summary is needed, then turn the summary back on.
Questions on this topic? See Which line items do not need a summary? in our Model Optimization Checklist forum.