With good quality lights flash tubes hardly ever blow usually it is miss use, if your putting on a softbox lay the softbox on the floor face down and mount the light to the box not the box to the light
Yes, Gary's got great advice: put the softbox on the FLOOR, and mount the light to the BOX!!! On modeling lights, never allow finger oils to touch the protective glass around the outside of the filament. Finger oils on quartz-halogen bulbs will form dark spots, where heat concentrates, causing premature filament failure. Also, when you switch OFF the modeling lights, always,always,always allow at least 30 seconds before moving the light or beginning to break down the set. When the filament is glowing, it is fine; but, when the filament is beginning to cool off, right after it is switched off, it is very vulnerable to shaking, vibrating, thumping, or any kind of "rattling" of the filament. When it is RED-hot and glowing or stone cold, it's tough and durable--but there's a very narrow window after powering OFF during which time the filament can eaaaaaaaaaaasily be broken. This period lasts only seconds.
Clean any accidental finger oil smudges with an immaculately clean paper towel and some alcohol. On a cool bulb, of course. Follow the no oils--cool down rule and modeling lamps, which cost $35 on some models of light heads, will last for a long,long,long time. Ignore them, and you'll run thru modeling lights like a frat house runs thru kegs of beer.