The type of process and product is also critical the clean is normally done by the maximum carry over
as determined by your API,S used.as well as micro biological and environmental monitoring.
Please note that this must be done based on worst case scenario eg. maximum number of people that could be in the manufacturing area including maintenance staff and staff doing sampling minimum of 3 batches in succession to be done.
Holding times again depend on process if you look at say solids manufacturing and you make granules and you for one or other reason have a break in the process you may get oxidation if this is wet for extended period and then you need to ensure there is not break down product but you would need info on DMF file to see route of syntheses. and have suitable method to detect this.
Sterile manufacture you need to ensure that the holding tanks after sterilization and transfer of the solution with the transfer line filling needles / heads with all the maximum staff and environmental micro biology samples as well as operators are done as set intervals to completion of the batch useing media fill medium and do 3 batches in secession based on the anticipated maximum hold time. also do full chemical analysis at start of batch and at end of holding time and after fill into final container
If you exceed this when actual manufacture take place batch will have to be reject.
You have to revalidated should you want to extend for longer period of hold time