God is outside of time; not bound to a linear series of events like human are. So, for example, if an item is blessed by a priest, it is blessed for all time. There is no need have that object periodically re-blessed. One-and-done. The same goes for some of the sacraments, such as Holy Orders, Matrimony, Baptism, and Confirmation.
I recall a radio program where a priest consoled a caller who was unaware of the severity of a loved one’s death and didn’t arrange for their Anointing of The Sick (last rites) in time. This priest used the same logic as mentioned above; namely God is outside of time and if we pray for the good intention of a departed soul after their exit, our good intentions are still efficacious, because in God’s eyes, everything happens at once.
Why wouldn’t absolution of sins work the same way? One is constantly in and out of a state of grace during their lifetime. As I understand things today, the only thing that matters is one’s state of grace at the moment of death (I’m talking Heaven-bound vs. the alternative). Why wouldn’t God recognize a person’s state of grace achieve at some point in their life coupled with the desire to behave in a sinless manner, rather than the linear progression of events inside the bounds of time. It’s hard for me to wrap my head around the idea that God leaves His timeless state to enter into a time-bound moment to consider if sin occurred in between that last two trips to the Sacrament of Reconciliation.