As discussed, if you have an iPhone, you should use the regular Suica via Apple Wallet. It does not expire after 180 days. I have not had an issue using it with more than 6 months' gap by adding amount to balance via Apple Pay (US-based MasterCard works at least - I have not tried Visa).

If you're going to Kansai, you can easily buy a physical Icoca from the ticket machines, as well.