Nothing ends a business trip faster than a paperwork problem at the border. The rules vary by country and change often, so the safe move is to verify rather than assume, even for destinations you have visited before.
Check three things early: passport validity, since many countries require six months beyond your travel dates, any visa or travel authorization you need, and the entry requirements specific to a business visit. Give yourself weeks, not days, because some approvals take time and rushed applications get rejected.
Carry backups. Keep a photo of your passport and key documents stored securely and separately from the originals. If something is lost, a copy turns a crisis into an inconvenience.