Methods and limits

How these notes are written, and what they cannot do.

Sources

Definitions come from general reference works and are linked where they appear. No statistics are quoted, because figures on waste, recycling and emissions vary by source and year.

Local rules come first

Repair rights, warranty terms, take-back schemes and waste rules differ by country and city. Your local authority and the product's maker are the authorities.

Safety

Lithium batteries can be dangerous if punctured or crushed. Leave battery replacement to a professional unless you have the right tools and guide.

Links

Outside links illustrate a point and are not endorsements. Some lead to pages in other languages and from unrelated industries, including gaming; that sector is not promoted here.

Contact

There is no lab or helpline here. Corrections are applied when pages are revised; each page shows its revision date.

Revised 2026-10-22