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Any parts that produce over 1W or so should require further evaluation for heatsinking or better component selection. The 1W number is not precise, and changes a lot based on package size, with larger packages having a lower thermal resistance and thus a higher max power in ambient air and without a heatsink.
Here is a great Application Note by Texas Instruments that explain PCB thermal design:
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https://www.powerelectronictips.com/heat-sinks-part-1-thermal-principles/
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