I am coming up on 4 years since I had my spleen out. I had it out about 6 months after diagnosis, and after steroids, IVIG, and 3 rounds of WinRho. I did it because my analysis is that it was cost-effective relative to those choices and had a good risk profile.
The analysis goes roughly as follows: I had spent $40,000 (insured, fortunately) on treatment by the time I had the splenectomy. It looked as if a minimum maintenance cost by medication would be about $40,000 per year with 6 WinRho treatments, or maybe somewhat less if Rituxan happened to work and hold a couple years. The splenectomy cost $20,000. Even to a pessimist, this has better than a 50% chance of really good results for a decade, which came to $2,000 per year for that period. With appropriate vaccinations (meningococcus, haemophilus influenzae B, and pneumococcus), the risk of sepsis is very low (it used to be a serious issue 20 years ago without these). With the skyrocketing costs of health care nationally, I think that these are real issues I have to consider, since ITP is an expensive disease to treat, and it comes out of other peoples' pockets.
So far, my platelet counts have been about 350k, and I have had no sign of excess illnesses of any type (2 colds in 4 years is all). I consider the outcome a great success.
Every treatment, medical or surgical, has its benefits and risks. Since I am a scientist who spends a lot of time dealing with statistical analysis of data, I made this decision fairly analytically, and considering its impact not only on me but on the medical system around me. There are many other ways to weight the various issues involved, and to come to different conclusions. The nicest way would not be to have ITP (or any other disease) in the first place, but that isn't the card we were dealt.
Take care, and good luck.