In addition to the mandated communal offerings, individual Jews were liable for, or permitted to bring, a variety of offerings of their own. How often did the average Israelite bring each type of offering in a year? Was this pretty routine, or unusual? (Sin-offerings and wellbeing-offerings seem like they could be pretty variable.)
The minimum of an average person had to go to the Bais Hamikdash for the 3 Regolim and that meant a Korban Olas Re'iya and a Chagiga. In addition, on Erev Pesach they had to bring a Korban Pesach (which was brought in groups as opposed to the individual). As far as how often a person would have to go to the Mikdash, even if a person is obligated to bring a Korbon s/he did not have to bring it straight away s/he had to bring it by the next of the 3 Regolim, if s/he did not then s/he would trangress a Mitzvas Asei. If s/he did not bring it by the end of 3 Regolim s/he would trangress a Mitzvas Lo Sa'saei as well. See Rosh Hashana 4a and rambam Hilchos Ma'asei Hakorbonos 14:13.