The official instructions tell an applicant to include a joining spouse in the initial application. Do not assume that waiting to add the spouse after the principal's approval preserves the same process or postpones the payment obligations. Confirm any proposed later inclusion with counsel and current instructions; under the reviewed terms the spouse adds US$15,000 and US$1 million.
Choose the household size once
Treat the question as a single decision made before filing: who is on this application. If the couple cannot fund two gifts now, the realistic choices are to delay the whole application until they can, or to file for one person and take separate advice about the other spouse's options. Ask what those options would actually be before assuming the second person can follow easily later.
Two considerations sharpen the one-or-two decision. Each person included is assessed on their own admissibility, so a spouse's record affects the household outcome as much as the principal's and should be screened before either fee is paid rather than after. And where the couple is weighing a delay, the terms of the program, the applicable amounts and visa availability are not fixed features of the world, so a plan built on today's figures deserves rechecking before it is executed.
Hypothetical example: a couple decides to wait eighteen months in order to fund both applications, and schedules a fresh review of the program terms and of their own records at the twelve-month mark rather than assuming the position will be unchanged.