Use 'infrequent' for services or events where regular occurrences are expected but do not happen often. Her visits to our home are infrequent, maybe once a year.
Pro Tip 2/3
Negative Connotation
In some contexts, 'infrequent' may imply a negative aspect, suggesting that more frequency would be better. I've noticed infrequent communication can lead to misunderstandings.
Pro Tip 3/3
Neutral Cases
'Infrequent' can be neutral, without implying whether its rarity is good or bad. Infrequent rain showers characterize the desert climate.