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ultimately long term buy and hold is the best strategy. Mining is a gamble. Difficulty follows the price as long as price keeps going up so will difficulty.

Disclaimer: I mine at home, cloudmine and hold. Because holding is boring for me.

A good mining strategy if you can get hardware at a reasonable price is 30/30/30.
30% of your mining earnings should be reinvested in hashes to keep up with difficulty. 30% hold long term and 30% cash out to have realized profit.

Good luck.

I'd definitely consider building a rig if you enjoy working with computers.

One thing to keep in mind is that Ethereum is currently going through the "Winter" period where mining will become exceedingly less profitable. However if you get in now you could make some money before the opp goes away. Afterwards you can use your rig to mine something else like ZCash.

Good luck!