I suggest dividing up internal audits into logical (easily manageable) scopes and have them scheduled throughout the year.
The key is to check:
1. The current processes are sufficient, without major gaps or inconsistencies.
2. Your current records and actual day-to-day activities actually reflect your procedures (i.e. you have evidence that you are doing what you say you should be doing)
For example, you might make a schedule at the beginning of the year into the following (loosely titled) categories:
1st quarter: design & development processes
- schedule dates for reviewing all related procedures and current records
2nd quarter: production processes
- schedule dates for reviewing purchasing, receiving, inventory/traceability, assembly...etc. processes. ...again check records for completion and accuracy as per your SOPs.
3rd quarter: management processes
- management reviews, internal audits, document control...
4th quarter: post-market and improvement processes
- CAPAs, NCRs, complaints...
The intent is to review everything at intervals that are reasonable. No hard-and-fast rule for "one year", though many companies operate this way.
When making a schedule, justify the intervals. For example:
- Standard processes: ones that have not changed in years, and have survived several internal audits without observations, might be scheduled at a lesser frequency (e.g. once every 2 years...)
- Problem areas: schedule several times a year if necessary. For example, if you have a history of problems with DHR accuracy, perhaps schedule a random internal audit of DHR records every quarter...
All the best!
MM