@jandob
HSAs are like IRAs, they are owned by individuals only. Because an HSA can be used to pay for medical expenses for the account holder, their spouse, and their dependents, there is no particular requirement for each spouse to have their own. However, it might be something that people want to do to diversify their holdings, or to make sure that assets are spread out equally between the spouses. For example, if Bob has an employer sponsored HSA, and contributes $100 per week via payroll deduction ($5200 per year), then either Bob or Betty could make an extra contribution of $2550 to bring them up to the 2023 maximum.
It may be the case that an employer sponsored HSA will have lower monthly maintenance fees than a private HSA, so that should be considered. It is also possible that a private HSA might have more investment options than the employer HSA; for example, if the employer HSA only offers a money market fund but a private HSA allows investment in mutual funds, you might want to take advantage of the higher investment potential of the mutual fund by putting some money into the spouse's HSA.
Lastly, if one or both spouses are over age 55, it is necessary for both spouses to have their own HSA if they want to maximize their contributions. At age 55 or over, each spouse is entitled to a $1000 catchup providing, increasing the family limit for 2023 to $9750. But the catch-up contribution can only be made to the account of the individual. So if Bob and Betty are both 55, Bob could contribute $8750 (the family maximum of $7750 plus his $1000 catch-up), but Betty's $1000 catch-up can only be contributed to Betty's account.
