How can one define luxurious beds and seats in the eighth precept? The precept, 


  Uccasayana mahasayana veramani sikkhapadam samadiyami


in eight precepts suggests that one should abstain from high and luxurious beds and seats. How should one define which bed or seat is not high and which one is not luxurious?

Can this precept be practiced at home?
It's an interesting question; for lay people, I've never been able to well-define this one. I usually translate it as "don't get attached to the pleasure of lying down or sleeping." But, we should probably go with the Buddha's words for monastics in the Brahmajala Sutta:


  "Or he might say: 'Whereas some recluses and brahmins, while living on food offered by the faithful, enjoy the use of high and luxurious beds and seats, such as: spacious couches; thrones with animal figures carved on the supports; long-haired coverlets; multi-colored patchwork coverlets; white woollen coverlets; woollen coverlets embroidered with flowers; quilts stuffed with cotton; woollen coverlets embroidered with animal figures; woollen coverlets with hair on both sides or on one side; bedspreads embroidered with gems; silk coverlets; dance-hall carpets; elephant, horse or chariot rugs; rugs of antelope-skins; choice spreads made of kadali-deer hides; spreads with red awnings overhead; couches with red cushions for the head and feet — the recluse Gotama abstains from the use of such high and luxurious beds and seats.'
  
  http://www.accesstoinsight.org/tipitaka/dn/dn.01.0.bodh.html


I would venture to guess that modern spring beds of all kinds could arguably be included in this list.