With Trezor I feel very secure
definitely not checking balances.
An example: actually a lot of the bitcoin gambling site owners also use Trezors (sometimes multiple) to store their funds. For example BetKing has more than 6k BTC in their Trezor devices. BitDice has 2k BTC in their Trezor devices. BustaBit also over 1k BTC. So if they trust that product with
that much money, we should be fine too
Just make sure to keep that backup (those 12 or 24 words) in a safe place where no one can steal it (and potentially consider situations like a fire that destroys both your backup and Trezor, if you want to be really safe.)
But the security of the device itself has been pretty well tested and proved itself imo.