For Schengen citizens multi-entries visa can or could be issued up to 5 years. As "business" or less common "cultural" categories. The 1-year has been the most common used.
for illustration this is my last 1-year multi-entry visa, "business" category.
the invitation in order to apply was the "electronic" kind, ie. a code sent to the consulate by FMS and PDF to the applicant. The date of validity were 12.04.22 - 07.04.23.
this is the former visa, 2 years duration, 27.07.19-21.07.21 and obtained by presenting a company letterhead, original not PDF (means stamp ink inside the paper mass, maybe embossing too)
when the cross-game of sanctions and counter sanctions started in 2022 between EU and Russia, it was right after I got that 1-year visa.
Prices for invitations inflated, then last year, visa processing fees also.
this is a 6-month "tourism" category visa, multi-entries, I opted for instead, because cheap price of invitation:
But, the next application for same kind of 6-month multi-entries didn't work,, probably because restrictions by citizenship. The end by Russia of the "simplified" visa regime for most of Schengen zone. Instead I got a double-entries 3-months visa:
for the consular fee now expensive, a double entries for 3 month is not interesting. So after that I got instead several evisas. Good for 2 weeks stays max, ok for a short stay, like an extra long week-end or a week, but then after few ones in a row, fees sum up to an amount.
All these visas pictures here were issued by Oslo consulate. Last year they declined applications on company letterhead invitations for 1-year or more, for many Schengen citizenships. A well as the 6-month multi-entries on regular tourist agency invitation. Maybe be related strict application of no simplified visa regime, many be local policy of Oslo consulate and/or the kind of invitation (telex, electronic, company letter).