Should an estate trustee hold back sale proceeds in case of future claims against the estate?

Often, yes, at least until the trustee is reasonably confident that claims like dependant support applications, unresolved creditor claims, or tax liabilities have either passed their relevant window or been resolved. Distributing all of the sale proceeds immediately and later discovering a valid claim against the estate can leave a trustee personally exposed, since a trustee who distributes assets without properly accounting for foreseeable claims can be required to make up the shortfall out of their own funds.

Because of this risk, prudent estate administration commonly involves holding back a reasonable amount from sale proceeds, or delaying final distribution, until known risks have been addressed, such as obtaining releases from beneficiaries, confirming no dependant support application is coming, and getting appropriate tax clearance. How much to hold back and for how long isn't governed by one fixed rule and depends on the specific estate, the nature of any known or anticipated claims, and professional advice on the relevant risks. A trustee unsure whether a holdback is warranted, or how large it should be, should get legal advice rather than either distributing everything immediately or holding funds indefinitely without a clear reason.