Quick answer: Sort bits into labelled zip bags or compartment boxes by army or part type, keep sprues flat and out of sunlight, and store the lot indoors — not in a damp shed.
Why bits storage fails
One mixed tin becomes archaeology. Label by project or by part type (arms, heads, weapons) — pick one system and stick to it.
Sprues
Keep uncut sprues flat in a box so parts do not warp. Cut parts go into bags immediately.
Link to army storage
Finished models need a different plan: how to store miniatures. Bits boxes are for the backlog, not the display shelf.
Display the keepers
Once a model is painted, move it to a shelf or cabinet rather than leaving it in the bits drawer. Ideas: display ideas hub.
Frequently asked questions
Plastic bags or boxes?
Bags inside a larger box are fine; hard compartment boxes win if you travel with bits.
Should I magnetise spare weapons?
Only if you swap them often; otherwise labelled bags are enough.
Can heat warp sprues?
Yes — keep them out of hot cars and lofts.
Metal bits?
Separate from magnets you care about, or they will migrate into one clump.
Keep instructions with the sprues they belong to, and separate sharp metal bits from soft plastic. A shallow parts box per project beats one mixed tin when you return months later.