With a linseed oil finish it’s never done. After a few months it is as water resistant as modern finishes, and it’s deep in the wood. When bumped or scratched the oil can well be 1/16 in into the wood.
However, in rain or humid weather it gets sticky, and needs to be buffed out and recoiled in between.
Soak it down, leave sit a week or more, buff, then THIN coat once a day for a week, once a week for a month, once a month for a year, then when ever you clean it and at least every few months from now on ad Infinitem.
Wax helps a lot, but linseed is never done.
This is why, as much as the dyed in the capote stitch counters and traditionalist love it, it is sant used in the old days.