It is not uncommon, particularly once children reach their teenage years, for living arrangements to shift. A child who has lived primarily with one parent since separation may decide that they want to spend more time, or even live full-time, with their other parent. Sometimes this happens gradually; in other cases it can feel sudden and unsettling. While much of the focus understandably falls on the emotional and practical impact, the financial consequences are often just as significant and, in some cases, more contentious.

The law recognises that teenagers have a certain degree of autonomy which increases the older they get, but that does not mean financial arrangements automatically adjust themselves if they go to live with the other parent. Whether child maintenance, benefits, or spousal maintenance change depends on a range of factors, including how long the move lasts, how care is actually divided, and whether the change is accepted by both parents.

Is it assumed that the financial arrangement will change?

There is no automatic assumption that finances change simply because a child says they want to live elsewhere. Financial arrangements only change when the reality of the child’s living arrangements changes, and even then, adjustments are not always immediate.

For example, if a teenager spends a few weeks or even a couple of months staying with the other parent following an argument, exams, or changes at school, this will not necessarily trigger an immediate financial reassessment. On the other hand, if the child has moved their belongings, enrolled at a different school, and is now living with the other parent on an ongoing basis, it is much more likely that financial responsibilities will need to be revisited. Essentially, what matters is not what parents call the arrangement, but how it operates in practice.

Does it matter whether the move is short-term or long-term?

Temporary arrangements rarely justify making financial changes, particularly if there is an expectation that the child will return to the previous living arrangement.

A useful way of thinking about this is to ask whether the move has become the new normal. If the child has been living with the other parent for several months, is registered with a GP in that area, and spends most school nights there, it is likely to be considered a long-term change.

Family courts and the Child Maintenance Service (CMS) are reluctant to respond to every short-term fluctuation in care. Teenagers, by nature, test boundaries and move between households so financial stability is generally prioritised over making constant recalculations.

What criteria decides whether a child has moved?

There is no single test, but several factors are typically considered together:

  • Where the child sleeps most nights
  • Where they are registered for school and healthcare
  • Which parent provides day-to-day care, such as meals, transport and supervision
  • Whether the arrangement is expected to continue
  • Whether both parents accept that the child has moved

For child maintenance purposes, the CMS looks at the number of overnight stays per year. If a child stays with one parent for more than 175 nights per year, that parent may be considered the primary carer. If care is broadly equal, child maintenance may be reduced or, in some cases, nil.

What payments might change?

The most obvious financial impact is on child maintenance, but it is not the only area potentially affected.

Child maintenance

If the paying parent becomes the receiving parent (because the child now lives with them), child maintenance may reduce, stop altogether, or reverse. This is not automatic and the CMS must be informed so a new calculation can be made.

If parents have a private agreement rather than a CMS assessment, that agreement should be reviewed. While private agreements are flexible, they can also become outdated quickly if circumstances change.

Child benefit

Only one parent can receive child benefit for a child at any one time. Generally, it is paid to the parent with whom the child lives most of the time. If the child moves, entitlement may change, and this can also affect other benefits and tax credits.

Universal Credit and other benefits

A change in household arrangements can affect entitlement to Universal Credit, Housing Benefit, and other benefits. For example, a parent who loses the primary care of a child may no longer qualify for certain elements, while the receiving parent may become eligible.

Spousal maintenance

Unlike child maintenance, spousal maintenance is based on the financial needs and resources of the former spouses, not directly on child arrangements. However, a change in where a child lives can indirectly affect spousal maintenance.

For instance, if spousal maintenance was awarded partly because one parent had higher childcare costs or limited earning capacity because of caring responsibilities, a significant change in care could justify a variation application. That said, spousal maintenance does not automatically change just because a child moves.

Would payments be backdated to the date the child moved?

This is a common source of dispute. Generally:

  • Child Maintenance Service: Changes usually take effect from the date the CMS is notified, not the date the child actually moved. This means delays in reporting can be costly.
  • Court-ordered arrangements: The court has discretion but is often reluctant to backdate unless there is clear evidence and a compelling reason.
  • Private agreements: These depend on what was agreed. Some parents agree informally to adjust payments from the date of the move, but this relies heavily on trust and clear communication.

Who should be notified of the change?

Depending on the circumstances, the following may need to be informed:

  • The Child Maintenance Service
  • HMRC (for child benefit)
  • The Department for Work and Pensions in relation to benefits
  • Local authority (for council tax and housing matters)

Failing to notify relevant bodies can lead to overpayments, arrears, or allegations of misrepresentation.

Do both parents need to confirm the move?

Where both parents agree the child has moved, changes are usually straightforward. Problems arise when one parent disputes the permanence or nature of the move.

The CMS can make decisions even if one parent disagrees, but they will require evidence. Courts are similarly cautious where there is disagreement, particularly if the move is recent or unstable.

Evidence of a move does not need to be complicated, but it needs to be consistent. Common examples include:

  • School correspondence showing the child’s address
  • GP or dental registration
  • Text messages or emails acknowledging the change
  • A revised parenting schedule
  • Statements from the child (depending on age and context). That said, it is worth remembering that financial disputes can place teenagers in an uncomfortable position. Asking a child to prove where they live can be damaging. Where possible, parents should aim to resolve matters cooperatively and keep the child out of adult disputes.
  • Proof of where belongings are kept

If there is one consistent lesson to be learnt from these situations, it is this: changes in living arrangements should be addressed promptly, calmly, and with proper advice, before misunderstandings turn into entrenched disputes.