Could I use land cards from let’s say 8th edition in my standard format deck? Or do I have to use newer cards?
As long as a card is legal in a format, you may use any printing of that card in that format, regardless of how old it is. Since basic lands are printed all the time and are legal in all formats, any basic land can be used in any format.
The one caveat is that if your lands are noticeably older and more worn than your other cards, they could count as "marked" cards. If you're playing without sleeves, you should avoid any visibly worn cards that you could spot in your deck.
Yes, unless they stop being printed in new sets
Lands follow the same rules as every other card in Magic, this includes basic lands. All copies1 of a card are legal in standard if a copy is in any standard legal set. From the Magic Tournament Rules section 3.3 on Authorized Cards:
The cards being played in the deck must be printed in a set that is legal in the format, even if the printing being used is from an otherwise illegal set. For example, it is okay to use the Stronghold printing of Mana Leak in Modern even though Stronghold is not a legal set for use in Modern.
This is determined based on the English name for that card (regardless of the language it's printed in) from the Comprehensive Rules:
201.2 A card’s name is always considered to be the English version of its name, regardless of printed language.
The five basic lands, Plains, Island, Swamp, Mountain, and Forest, have been printed in almost2 every set, and this means that since there has always been a set in Standard containing a copy of these lands, all copies of these lands are legal to play in Standard.
This applies to the regular 5 basic lands. The Snow-Covered versions are currently legal until Kaldheim rotates out in September 2022. Wastes, the colorless basic land, are not currently standard legal since Oath of the Gatewatch rotated out in September 2017.
Old cards can be damaged and worn. Using older lands is fine by all these rules so far, but if the cards can be identified in your deck because of their age, they count as marked and would be illegal for tournament play. Using opaque backed sleeves can get around this problem. From the Magic Tournament Rules section 3.3 on Authorized Cards:
Significantly creased cards can be distinguished from other cards in a deck, even sleeved. Also, altered cards may be thicker than the other cards in the deck, depending on the method used to alter the card. If any cards can be distinguished from the other cards in the deck without viewing its front face, then those cards are marked and not legal for tournament play.
- Excluding the gold bordered World Championship deck copies which are not legal anywhere.
- Some sets did not have any basic lands (Arabian nights famously, except for the accidental mountain, most recent example Dragon's Maze), some sets have had snow covered basic lands instead (most recently Kaldheim)