This is an important question asked by many devotees of Hariharasudhan Ayyappa. As you might be well aware that the temple remains continuously open annually only for two months starting from November 16 to January 20. At other times you need to make the visit during the 5 day pujas held in the beginning of a Malayalam month that is around 15 to 19 of every month. Apart from this you can also visit the temple when there is the 10-day Vishu puja (April 10 to April 18), the yearly festival (March) and during the Thiruvonam puja.
How many times can we visit Sabarimala in a year?
The answer is you can visit any number of times you want when the temple is open. There is no restriction regarding the number of visits.
There are staunch Ayyappa devotees who visit the temple every month. Some devotees visit during month in which they have some special puja. Some devotees visit in alternative months.