We primarily use a Google Sheets spreadsheet with multiple tabs for trip planning and re-use the format for different trips. In Google Sheets, our main worksheets are: a main summary&planning tab, travel tab, and accommidations tab with secondary tabs like budget/spend, climate/sunrise/sunset, time zones, cell phone, key URL's, etc. We generally only link date and city info across the sheets.
We still use TripIt superficially for flights but it's not our main tracker because it doesn't have a summarized view in the format we want, it can't handle the confirmation emails of many of the accommodations we book directly with (so we would end up having to manually enter anyways), and there's certain info it doesn't track that we want a view of.
Beyond the spreadsheet, we keep a Google docs doc to gather key info for the city and a folder in gmail to store all of our confirmation emails/correspondances for the trip.