I agree with the above posters that your port SHOULD be flushed every 4 weeks
The longest my port has gone inbetween flushes is just over 2 months lol
I know Im bad, but to justify it, my port is 7 years old, I am 3 years post tx. I find I have really thin blood anyway, and ontop of that being on continuous pred its even thinner...So I havent had any problems with flushing it every 2 months, I been doing the every 2 month flush now for 2 years, with no problems....
however that said I would NOT recommend anyone extending this time frame for normal CF port users, Since Im post tx its not as vitally important that my port stays working....drs have been wanting to take it out now since my tx, but I have needed it, and due to poor veins, I have just kept it in!