And here I was spending all of the money my parents had saved their entire life.
张道真《现代英语用法词典》(首都师范大学出版社,P569):
For 表示时间长度或距离。
for(如果紧跟动词)有时可省略:
The performance lasts (for) three hours. (DCE)
We stayed (for) three days [a week, a long time, etc.]. (Palmer)
We walked (for) a mile and ran (for) a mile. (Palmer)
The forest stretches (for) a long way. (Palmer)
Will you be out (for) long? (DCE)
The desert stretches (for) many miles. (DCE)
葛传槼《英语惯用法词典》:
1.for two hours, for three weeks, for many years, for several miles 等表达方式里的 for 有时省去,但在正式些的文字里最好不省去。有下面两点该注意:
(1)在句首通常不省去,如 For two hours he had been waiting 里的 For 通常不省。