A mid-sized manufacturer walks into a scoping call. Their ECC 6 is aging. Their HR module has three integrations and one is broken. Payroll runs on a bespoke tool that talks to SAP via CSV. They know they need to move. They want to know what to move first.
The honest answer: it depends on what’s on fire.
Here’s the short version of how we help clients decide.
S/4HANA first — when the ERP is the constraint
Go with S/4HANA first when:
- ECC 6 support timelines are your immediate problem. Mainstream maintenance ended December 2027; extended runs to 2030. If you’re 12–18 months from a hard cutoff, you don’t have the luxury of ordering the moves.
- Finance close is your bottleneck. S/4HANA’s Universal Journal collapses financial reporting from days to hours. If your CFO is the loudest voice in the room, this is where the ROI conversation starts.
- You’re on multiple ECC instances after M&A. Consolidating during the S/4HANA move is often cheaper than migrating twice.
- Your industry-specific processes are already close to standard. Discrete manufacturers on classic ECC MM/PP tend to have less bespoke customisation, which makes a Greenfield or Bluefield migration tractable.
The catch: an S/4HANA rollout is a 12–24 month program even for a mid-sized business. The value shows up gradually. Nobody notices the day you go live except the finance team.
SuccessFactors first — when the people-side is the constraint
Go with SuccessFactors first when:
- You’re losing hiring cycles to slow onboarding or messy performance tools. SuccessFactors’ Employee Central + Recruiting is the fastest visible win we typically deliver — 3–6 months for a mid-sized rollout, and people feel it every day.
- Your ECC HR is heavily customised and expensive to maintain. Retiring the customisation debt inside ECC HCM by moving to SuccessFactors is often the actual reason to do it. Don’t say that in the business case, but know it.
- Compliance changes are your recurring pain. Cloud-delivered HCM absorbs statutory changes for you. If you’re running a large payroll operation across states or countries, this matters.
- You want the leadership team to see a win before the ERP program starts. Modernising HCM builds internal credibility for the harder S/4HANA conversation.
The catch: SuccessFactors doesn’t fix your ERP problem. If your finance close is broken, moving HR to the cloud doesn’t help.
When we say “actually, neither yet”
Sometimes the honest answer is:
- Fix your master data first. If your customer or material master is a wreck, S/4HANA won’t fix it. It’ll just make it faster.
- Fix your integrations first. If you have six point-to-point integrations bolted onto ECC, you’re going to spend six months untangling them either way. Do it now, as a separate project, with a defined outcome.
- Consider a phased ERP-side approach — but keep it phased. Central Finance is a legitimate stepping stone. So is a two-tier ERP for a subsidiary. Neither is a way to avoid the eventual full S/4HANA move.
What we recommend for the manufacturer above
For that manufacturer with ECC 6, three HR integrations and CSV-fed payroll:
- Six-month HCM assessment leading into a SuccessFactors Employee Central + Recruiting rollout. Solves the visible pain, gives leadership a Q4 win.
- Parallel: master-data cleanup and integration inventory. Boring, cheap, and directly enables the ERP program.
- Q2 of the following year: kick off the S/4HANA program. Now with cleaned data, cleaned integrations, and internal credibility already banked.
That’s the sequence we’ve run at four clients in the last five years, with one variation: at a fifth client, ECC 6 support pressure was so severe we had to invert it and did S/4HANA first with a stopgap HR extension. It worked. It was also more expensive than the reverse sequence would have been.
Two things worth stating out loud
One: the vendor-recommended answer is almost always both, in parallel, run by a large systems integrator. That works for large enterprises with the budget and internal capability to run two mega-programs. Mid-sized businesses can’t.
Two: the actual ROI on either program comes from the process re-engineering you do around the technology, not from the technology itself. Budget for BPR from day one. That’s where the money goes and where the return comes from.
If you’re wrestling with this decision, we’re happy to have a scoping call. No slide deck, one senior consultant, an honest recommendation.
