Engineers and scientists once used drafting boards, calculators, and typewriters in their day-to-day office work. All of engineer use computers instead of calculators for complex calculations; some of they use computers in place of drafting boards; and increasingly large numbers of engineers and scientists use computers instead of typewriters to produce written documents. Some engineers and scientists need to be able to send and receive information to and from other computers. Some want to be able to switch quickly between spreadsheet or database programs and their word processing program as they calculate and collect information for whatever they are writing. All word-processing products have come down in price even as their quality has been improving, but those trends are most evident in the field of low-cost printers. The computer hardware and software needed to communicate with other computers are often sold together.