On a average how long does a catch dog last?

As said before this is an impossible question to answer because there are to many variables. I didn't notice that anyone mentioned tracking systems. I have been using the garmin gps tracking system now for about a year and i know exactly where my dogs are which direction there headed and the quickest way to get to them. I have a good sized leggy rednose with a pretty darn good nose that get gone on me and run down a hog and with the gps i can get there in a hurry. I also think the weather is a big factor. I'm from florida and during the summer it is just to hot to run the vests and cut collars especially during the day and for this reason i hunt at night a lot. Just my 2 scents on this topic.