That depends. I’ve seen a lot of adaptation to processes that are legitimately & measurably better in time & accuracy ignored in favor of costly customizations out of nothing more than “not created here” syndrome. If a customer doesn’t like that then an off the shelf product is the worst choice they can make unless they are prepared to hire a significant in house dev team.

Otherwise, if you have been adapting your current business processes to deal with the limitations of a legacy system first deployed in the early 80's then there's an excellent chance that at least some of those things can be done more easily in a more modern system. (Though SAP may not always be the best place for that to actually be the case).

Every. Single. Customization. You make, which makes so much sense to seemingly eagerly satisfy the user during implementation, will be a massive pain, forever, with every patch and upgrade and new functionality released by vendor in perpetuity, and will inevitably cause performance and failure issues eventually. And will only be getting more expensive and painful to maintain exponentially over many years.

Yes, you should customize erp for your very specific edge cases that you a absolutely need. But:

A) number of processes Bob from accounting or Fatima from HR believe are absolutely crucial and immutable and special and unicorn and mandatory, is way way higher than processes which actually are special and must be preserved. Personal inertia is huge. More often than not, special ways of doing things which are not your core business are an unnecessary cost, whether through erp or not.

This may seem like I'm a traditional grognard IT head who disregards users and their needs, but it's quite the opposite so let me clarify with

B) The threshold of customization at which erp no longer makes sense is in fact very very low.

If you actually, really properly are a special snowflake of a company and your convoluted hr or finance or pay processes are your key immutable competitive advantage, then don't get an erp. Other name for erp is cots, commercial off the shelf, which strongly hints as to how its meant to be used. With erp, customizations should be fought tooth and nail on every level,and that's a largely accepted industry wisdom.

> I don't work with SAP ..

Yeah.. that's just it. Your experience doesn't matter. Adjusting your business to fit SAP nearly as much as an unspoken requirement. It's not just a smart bit of wisdom people throw around. It's literally what you have to do if you want to have any hope of implementing SAP successfully, because it is such a colossal, messy charlie-foxtrot that there is no hope otherwise. Not even SAP's own people understand their own mess.

Adapting Dynamics ERP to business process is a challenge of its own, and not every company can do it. At least it's possible in Dynamics, SAP is a mess - most customers I know with SAP have to use external software and import/export for significant customization.

But then, did you really gain anything by using an ERP instead of just a dumb database, which would have worked just as well as backed for those applications?