Define "industry experience"...
As it pertains to the definition of working for a company and picking up tidbits from there: no, this is not mandatory at all.
As it pertains to industry experience as it pertains to getting a mentor from the industry or surrounding yourself with peers who have industry experience: yes... Sooner than later, but not day 1.
Learning with / from those in the industry provides insight into the nuances you'll never get by yourself: code that is written well because ONE DAY someone may take over the coding while you concentrate elsewhere. Good code that can be picked up / understood easily is worth it's weight in gold.
If you are thinking of expanding one day to more than just yourself the surrounding yourself w/ I dustry folks can help you learn about good programming practices within groups.
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