Looking at what other employers outsource is a reasonable way to sanity-check your own plan, provided you read the pattern rather than copying it. The order in which employers move work is consistent, and the reasons behind that order are more useful than the order itself.
What goes first, and why
Payroll processing and tax filings, almost universally. They are deadline-driven, they carry penalties, they need no knowledge of the business, and there is a competitive market with published prices. Every characteristic that makes work suitable for outsourcing is present at once, which is why this is the near-universal starting point rather than a coincidence.
What goes second
Documents and compliance calendars, usually when an employer crosses a size or a state boundary and the paperwork stops fitting in the gaps of somebody's week. This is where the decision becomes a real choice rather than an obvious one, and where employers most often over-buy by taking an advice tier they will not use.
What employers keep, and the ones who regret giving it up
Hiring decisions, performance conversations and first-line employee questions. Employers who route everyday staff queries to an external line usually pull them back within a year, because the efficiency is real and the message it sends is worse. That is the most common reversal in this market and it is worth knowing before you make it.
Questions people ask about employers outsourcing
What do employers outsource first?
Payroll processing and tax filings, almost universally, because they are deadline-driven, carry penalties, need no knowledge of the business and have a competitive market with published prices.
What do employers keep in-house?
Hiring decisions, performance conversations and first-line employee questions. The last is the most common thing employers outsource and then take back.
When does the second wave happen?
Usually when a business crosses a size or state boundary and the paperwork stops fitting into the gaps of somebody's week. That is also where over-buying is most common.