In circuit programming is just such a huge step forward. You still need separate programming hardware, but you don't need to pop the chip out. Beyond that, a f

In circuit programming is just such a huge step forward. You still need separate programming hardware, but you don't need to pop the chip out. Beyond that, a few hundred bytes is usually enough for a simple bootloader. That tends to accelerate things even more. And writing bootloaders tends to be fun. I've done a tinyusb bootloader on an attiny45 with the user program sharing the v-usb stack in the bootloader and also a CEC bootloader. The CEC one of course took several minutes.