Here are some places locally to get your bow re-haired, new bridge, strings, cracks fixed, etc.
Matt Wilson 406.549.0889
John Sporman 406.241.8488
Peter Barberio 406.549.1502
Mark Hollinger 406.542.2012
If you play: (this is a very general rule of thumb)
1.5 -3 hours a day-- replace strings every 4-6 months
1 to 1.5 hour a day -- replace strings every 6-9 months
30 minutes to 1 hour a day -- replace every 9- 12 month
I am more than happy to put on new strings if a student needs assistance.