The main reason for condom failure is incorrect usage. They seldom leak or break from faulty manufacture.

Date: Mon 21 Dec 87 17:47:34
From: Chucker P (on 104/40)
To:   Doug Mosher
Subj: Condoms

 >  There are more arguments about how safe condoms are. My private opinion
 >  is that there is some unsafety relating to breakage, leakage, and
 >  occasional mistakes or omissions (which I also believe explains their
 >  less than perfect contraception record).

According to Clark Taylor, PhD:

The main reason for condom failure is incorrect usage.  They seldom leak or
break from faulty manufacture.

TIPS: (1) Keep a convenient supply in a cool dry place for "every time"

      (2) Don't test rubbers by stretching or inflating them.

      (3) Use them EVERY TIME you have sex.  (I personally doubt the need
          for condoms with oral sex).

      (4) Open the package carefully.  Tearing it can damage the condom,
          especially if you have long or jagged nails.

      (5) Gently press air out of the receptacle tip before putting it on:
          AIR BUBBLES CAUSE CONDOMS TO BREAK!  Plain ended types require
          that you leave about 1/2 inch free at the tip to catch the sperm.
          A DAB OF LUBRICANT INSIDE THE TIP will solve the air problem and
          greatly increase sensation... the condom slips on your cock like
          a foreskin does!

      (6) Unroll the condom so that it covers the entire ERECT penis.  If
          uncircumcised pull back the foreskin before covering the head
          with the condom.  Fitting the erect penis ensures the best fit
          but if it is soft be sure to roll the entire condom down to the
          base as it gets hard.  Eliminate any air bubbles.

      (7) Use plenty of water soluble lubricant on the outside of the condom
          and on the anus (or vagina) before entry.  Cavities that are too
          small or too dry can pull condoms off and tear them as well.  Oil
          based lubes like Crisco and Vaseline cause the latex to
          deteriorate very quickly and gum things up.

      (8) Hold onto the base of the rubber and your penis when you need to
          so it won't slip off.  If you are getting soft or your partner is
          very tight the condom may tend to slip.  Holding onto the base
          will solve the problem.

      (9) After shooting, hold onto the base to avoid spilling sperm or
          losing the rubber inside your partner.  Pull out gently.  (Both
          are good form).

      (10) Throw it away - use only once!
 * Origin: The Aerie, Denver, CO, (303)-623-7865 (Opus 1:104/40)