Should every vote be counted before a winner is declared, even if it means not knowing the total count on Election day?
Of course. Plenty of elections were not decided until well after election day and the Republic survived. Would it survive throwing millions of votes in the garbage?
Of course. Every vote legally cast within the time frame specified in the individual states should be counted. As far as calling the election goes, the battleground states are the only ones that could hold things up. Most (Arizona, Florida, Georgia, Michigan, & Wisconsin) don't allow for ballots to come in after election day. North Carolina and Pennsylvania are currently allowing ballots postmarked by election day to come in up to three days later, but there is litigation pending in both states that could block that. Iowa and Nevada are the swing states that could hold things up for about a week if the election is tight. Illinois and California are the delay champs, with ballots coming in up to two weeks late still able to be counted, but Trump has zero chance in both of those states. https://www.buzzfeednews.com/article/addybaird/vote-by-mail-state-deadlines