We had our boat shipped to us in Toledo from Maryland. We knew just from visual inspection, and the years of service on salt water that we needed to replace the shrouds. We had them all done the winter we got her (she arrived in late-October 2014). Our local sailmaker gave us a good deal and shipped the old shrouds to a place in New England (no, they didn't disclose who the rigger was).
We stepped the mast ourselves at the local sailing club. It was quite an ordeal because the mast was almost too tall for crane. One tip: have some cardboard and or carpet handy to hold between the bottom of the mast and the bulkhead wall of the head... just in case it goes out of alignment, and scratches the $&%@! out of your paneling.
It did go without incident. And I have to say that if you are in calm water and light winds, I see no reason to worry about having your spar up for a short while with no shrouds.
What I would recommend is doing the lowers and uppers at different times. One set or the other will support the mast easily with no sailing load on it. Additionally, use of halyards would be a great way to limit excess sway or movement if there is an issue. It would certainly be a good precaution.
8 Shrouds total and they are pretty good size. I seem to think it was around $1700 but I might have been as high at $2500... as I am going from memory here.
The new turnbuckles were so shiny they made the rest of the boat look bad.