Keep your speaker cables short while using large gauge wire. Signal loss diminishes the value of your system. Similar, but not the same. Make sure that you buy your sound system wisely. If you are planning to expand in the future and require more from your current equipment, buy the most efficient speakers possible so that adding on is cost effective.
More efficient loudspeakers cost more.
To spend less money in the long run, be prepared to pay more now. Microphones Buy the best microphones that you can. Inexpensive microphones are manufactured with less stringent tolerances, thus creating the potential for problems. You get what you pay for. Keep microphones and speakers as far apart as possible without sacrificing proper speaker placement.