 One of the most popular arguments against wider sentence spacing is that it was created for monospaced fonts of the typewriter , and is no longer needed with modern proportional fonts . However , proportional fonts existed together with wide sentence spacing for centuries before the typewriter , and remained for decades after its invention . When the typewriter was first introduced , typists were most commonly taught to use three spaces between sentences . This gradually shifted to two spaces , while the print industry remained unchanged in its wide em @-@ spaced sentences . Some sources now state it is acceptable for monospaced fonts to be single spaced today , although other references continue to specify double spacing for monospaced fonts . The double space typewriter convention has been taught in schools in typing classes , and that remains the practice in many cases . Some voice concerns that students will later be forced to relearn how to type . 
 One of the most popular arguments against wider sentence spacing is that it was created for monospaced fonts of the typewriter , and is no longer needed with modern proportional fonts . However , proportional fonts existed together with wide sentence spacing for centuries before the typewriter , and remained for decades after its invention . When the typewriter was first introduced , typists <a href='uninflect' title='1'><mark>were</mark></a> most commonly taught to use three spaces between sentences . This gradually shifted to two spaces , while the print industry remained unchanged in its wide em @-@ spaced sentences . Some sources now state it is acceptable for monospaced fonts to be single spaced today , although other references continue to specify double spacing for monospaced fonts . The double space typewriter convention <a href='been_done' title='2'><mark>has</mark></a> been taught in schools in typing classes , and that <a href='uninflect' title='3'><mark>remains</mark></a> the practice in many cases . Some voice <a href='uninflect' title='4'><mark>concerns</mark></a> <a href='null_relcl' title='5'><mark>that</mark></a>students will later be forced to relearn how to type . 
One of the most popular arguments against wider sentence spacing is dat it was created fa monospaced fonts of da typewriter , and ain't no longer needed with modern proportional fonts . However , proportional fonts existed together with wide sentence spacing ffacenturies before the typewriter , and remained for decades after its invention . When the typewriter was first introduced , typists was most commonly taught to use three spaces between sentences . This gradually shifted to two spaces , while the print industry remained unchanged in its wide em @-@ spaced sentences . Some sources now state it is acceptable for monospaced fonts to b single spaced todayy , although other references continue to specify double spacing fofironospaced fonts . Tdadouble space typewriter convention done been taught in schools in typing classes , and that remain the practice in many cases . Some voice concern students will later be forced to relearn how to type .