if you work in business environment they will expect a presentable beard also you can have a solid beard that looks neat not filthy.Have started rocking the beard again. Am particularly impressed by the patches of white repping my old age.
As for Beard Trimmers, The Fuck? You don't trim a beard, as they say on Frozen "let it grow, let it grow".
That said I haven't trimmed my beard in a few months but its longer than the trimmers range anyway.