The word 'hodo' basic meaning has a relation with 'the range' or 'the level', 1)related to the amount (means;almost/about) :30分ほど歩いた（time range),10キロほど離れた（distance range),10人ほど参加した（amount) 2)related to the level or range of doing things 知れば知るほど難しい。 (the more you know, the more it is difficult) 君の日本語は上手だね。それほどでもないよ。（your japanese is very good. oh, it is not so good) 食べるのもほどほどにね。（Don't eat too much)

i think in addition that hodo ＝ about there is another use of it: ex: あのときほど、面白かったことはなかった。 there is no time more interesing than that time.

hodo ＝ about ex: 私は30分[ほど]テレビを見ていた。I was watching TV for about 30 minutes. （watashi ha 30pun [hodo] terebi wo mite ita.）