/boot should now default to 1 GB

I installed Ubuntu 20.04 amd64 with disk encryption and defaults.

This created a 500 MB partition for /boot, with an ext4 file system, leaving 457MB usable space.

Each full kernel + initrd image + system map + config takes about 100MB (maybe a few more or less), The space needed in standard operation are two such sets, plus one more during updates (while the initrd is built, and before old kernel images are automatically removed). So about 300 MB.

However, if you would like to also install a mainline kernel image, and then an update to that, you will run out of space.

In most situations, disk space is very affordable nowadays, and I think that not having users run into this out of space situation (which also 'breaks' apt in that there will be a package needing fixing) is most desirable if it can be achieved by just raising the default for /boot to 1 GB.