「みなし再入国」って1年以内ならOK?一時帰国前に確認したいこと

Planning a trip home this summer and want to make sure I don't mess up my status. From what I understand, if you return within 1 year (and within your period of stay), you can use 'みなし再入国' (special re-entry) — just tick the box on the departure card and show your 在留カード, no re-entry permit needed. A few things I want to confirm: ・what if my 在留 expires while I'm abroad? ・over 1 year → need 再入国許可 in advance, right? ・anything customs/immigration trips people up on? Anyone done this recently? Want to travel stress-free ✈️