The Common reason of ESIC & PF Inspection will be conduct:-

If employees' strength increased unexpectedly.

if employees' strength decreased unexpectedly.

if non compliance of esic & pf.

if challan not paid by company more than 3 months

if any complaint of a company by employee name only

if pf & esic any notice reply is not filed by employer 

if claim, Correction cases increase unexpectedly.

if wrong return filed of esic & pf by employer.

if any demand is not paid by the employer.

If a company gives a request for closure of the company.

if contribution is decreased unexpectedly.

So please check your company's compliance from time to time to avoid inspection.