The oils can also be "topped up". So a priest can go a long time without going to a bishop.
The more important question is who is going to ordain his seminarians?
I have heard this, but it makes no sense. Why would the Church require old oils be thrown out and new ones obtained if the oils could just be topped up?
Also, how many times can they be topped up?
Can a priest do this several years in a row?
Where are the rules for this?
Off topic, but o.k.. Ordination is not the only need a seminary has for a bishop. There are minor orders. And a seminary operates uncanonically without a bishop attached to it.