ugh i voted wrong on the poll, you have
'detachable box magazine (internal magazine)' and i only noticed what was in brackets.
leaving a mag fully loaded with the spring under tension all the time actually doesnt weaken the springs - even over extended periods of time like 20+ years. this goes against common sense but its true.
the only thing that ends up weakening springs is repeated compression/expansion cycles. so people who constantly unload/load their magazines to 'save' them are actually doing much more harm than good.
what does
really damage mag springs is bending them beyond their elastic limit such as forcing in extra rounds (like forcing in 31 or 32 rounds into a 30 round mag), or modifying/adjusting the mag by bending the spring by hand.
that said i prefer the floorplate system. up until last month id have said detachable mag, but three very recent events changed my mind:
1 - i just broke the small folded metal detent tab on my Savage magazine, making it wobble all over and have feeding issues. i had to duct tape it into the gun (Canadian engineering at its finest) as a temporary fix. Savage actually fed-exed me a replacement that i received
one day after i called them (wicked service), but this drove home the point that the chance of a mechanical malfunction is much higher with a detachable magazine than it is with a sturdy old floorplate.
2 - i forgot my magazine at home just recently

. the
shame... and i was
just making fun of people who forgot their mags a month ago. i store my guns in the cabinet with the magazines removed and i was in a hurry and completely forgot the magazine - although i had plenty of ammo. since there is a huge gaping hole in the action of the gun where the mag normally sits, actually having to
chamber rounds in your new single-shot gun with gloved fingers sucks, believe me.
3 - someone pointed out that with a floorplate you can just open the floorplate and dump the rounds in, snap the floorplate shut and off you go. it never would have occurred to me to do this, for some reason i just naturally assumed floorplates were there to dump shells, not load them... but now that ive tried it its a
very fast way to load your gun... although slapping an already loaded mag into the gun is still the quickest.
IMO the one big advantage of detachable mags involves the Canadian gun storage laws. if you store your non-restricteds in a locked gun cabinet/safe, you can have a stack of loaded magazines sitting right there on your shelf. so you just need to unlock your cabinet/safe, take out the gun, slap in a mag, and youre good to go. so when the zombies come, you dont have to waste precious moments fumbling with loose ammo and loading your internal magazine.