Dachshunds should live between 12-15 years on average. If they aren't then you are doing something wrong. Seriously, here are some hints on keeping dachshunds fit and healthy.
Fat - It is very important to not overfeed your dachshund. If you do, then the resultant weight will damage the dogs back! If you have been known to spoil your dog with treats then please think of the implications. Stick with a well balanced diet. Small and often feeds will keep the fat off.
Injury - Again the back is very susceptable to damage. When you handle your dachshund, make sure to keep a hand under the dogs stomach, thus supporting their long spine. Their long spine must also be a consideration when playing with your pet, they cannot be allowed to jump off the sofa. This could cause slipped or damaged disks.
Housetraining - I have researched this and from what I have found on the net and my own experiences, they are not 100% reliable when it comes to house training. Mainly because they often suffer from over excitability. Dachshunds must have been at the back of the queue when they were handing out bladder control.