Recommendations:
 
For Natural:
1. No Medical Diagnosis: 6-12 CYCLES
2. Medical Diagnosis or 1 Miscarriage: 12-18 CYCLES
3. 2+ Miscarriages or Severe Medical Diagnosis: 2-3 years - If you have any failed IUI or failed IVF, I request 2-3 years. 
 
For IVF: 2x a week until transfer = 6 months
I strongly recommend 6 months instead of 3 months (not as high of success rate if you do 3 months).
or
Or 3 months MINIMUM prior to retrieval (3x a week) and then 3 times a week prior to transfer
Also:
During the month of your IVF - prior to retrieval and prior to transfer: 3+ times a week

For IUI: 2+ times a week = 6 months
I strongly recommend 6 months instead of 3 months (not as high of success rate if you do 3 months).
or
3x a week = 3 months
Also:
For 30 days prior to your IUI and until you find out your pregnancy results: 3+ times a week