The standard advice is that changing employers raises pay faster than staying. That is often true and it omits what a move costs internally.
Tenure buys things that do not appear in salary
An employee who has been somewhere several years knows who decides what, which processes can be shortened and whose approval is required in practice rather than on paper.
That knowledge is not portable. A new employer resets it to zero, and the first year elsewhere is spent reacquiring what was already held, during which output is lower and visibility is thin.
Vesting schedules, accrued leave and internal reputation reset similarly, and the size of that reset is frequently larger than the headline difference between two salary figures.
An internal move changes the work without the reset
Transferring teams changes the manager, the projects and often the function, while preserving the network, the institutional knowledge and the record of past performance.
Because the receiving manager can talk to people who have worked with the candidate, the hiring risk is lower on both sides, which is why internal candidates are frequently placed faster.
The visible cost is pay: internal moves often carry smaller increases than external ones, which is the point at which most people stop doing the arithmetic.
The pay difference is smaller than it looks
An external offer usually includes a premium for the risk both parties are taking, and part of that premium is spent on the unproductive first months.
Internal moves also compound differently. Two internal moves in four years can end higher than one external move, because each builds on a record the employer already trusts.
Where the folk wisdom is right
When an employer's pay bands are genuinely below market, no internal path corrects that, and the only route to market rates is a different employer.
The same applies when a function does not exist internally, or when a reputation formed early has hardened in a way no transfer will dislodge.
The conversation is the obstacle
Internal moves require telling a current manager, which people avoid because they expect it to be taken as disloyalty and because it cannot be undone once said.
Most organizations have a stated policy on this, and reading it before the conversation converts a social risk into a procedural step with known rules.
Where a policy is unclear or an employee fears retaliation, a human resources representative is the internal route and an employment attorney is the external one, since protections vary by state.