does any of the following make an attiny84 chip non reprogrammable?

I wanted to ask this , because I was getting no information online and I wanted more control over the (hardware ) features of attiny to make as much use of stuff as possible .
so - does doing any of these make an attiny84 unreprogrammable using the arduino uno as ISP?

  1. playing with timer0
  2. playing around with USI without resetting the registers to initial values at end of loop
  3. mistakes while setting up the wdt
  4. passing a sleep command in assembly after setting registers for a power down
  5. playing with the ADC registers
    please answer this because I want to know them before I do anything to the hardware and by mistake make the chip unreprogrammable. I live in a country where attiny needs to be imported and I can't buy the attinies again and again . sorry if this is a stupid question any tips will be very nice.

None of the above will make the attiny unreprogrammable. All the registers involved are "volatile" and will loose their settings when power is removed.

Some of the non-volatile chip configuration registers, known as "fuses", can make the chip difficult to reprogram without specialist equipment. For example, by setting the fuses for an external 20MHz crystal means it cannot be reprogrammed without actually attaching an external 20MHz crystal. Setting the fuses to disable the reset pin, so that it can be used as an extra input pin, cannot be undone without an expensive "high voltage programmer" device.

thank you so much! and i will not play with the fuses(i have them set up for internal 1 mhz clock so will not play with them.)but i had a doubt(sorry for that) so can you pleeeeeeaaaaaseeeeee explain me what happens when the chip is reset? i mean are the registers(port ones and usi ones) set to their correct values for programming when a system reset occurs? please tell so that i could immediately use my tinywireM library that i downloaded months ago? can you also tell me some of the things not to do (which can make the chip unreprogrammable ? i was afraid every time that i did something or played around with the hardware stuff)

hi, i used USI , it works , the thing now is that the attiny (instantly after programming) tries to take control of sck line (it coincides with the spi sck line ) so i added 2x 8k resistors in series to data lines and clock lines works fine , using two wire mode, reprogrammed successfully after that upload also(successful because i was greeted with "done uploading and "avrdude done, thank you. " in the black space down the blue bar and had a nice blinking led.) thank you so much. trying out the other stuff mentioned in the question. i hope that works well too!