Looking in the coin book, you will see that they were minted up till the late 1920s or early '30s (depending on the denomination). But your question is: "Up to what approximate year were gold coins
normally used?" I would say that the answer to that is that very soon after the turn of the century, very little were carried around as they had been before in pocket-fashion. If you were to survey all the md'rs, for instance, who have found gold coins, very few ever post-date 1900. Most are pre 1900 dates. For example: I have 11 so far, and only 1 is in the 1900s (a 1914s $2.50). Of all the gold coins I can think of that've been found in CA that I can think of (30 or so just off the top of my head), only 1 or 2 others were after 1900-ish. Not sure about east coast.
I believe the reason for this is that times were changing in the 10s, 20s, & 30s. Paper money was becoming more widely used. Telegraphing larger amounts was becoming safer than carrying one's life-savings while moving/travelling, checks (drafts written against banks) were becoming more widely used, etc...
I suspect that at all times in those days, gold coins were taken out for large purchases, and not used like pocket change, in the sense we think of today. Ie.: they'd be your "savings", only taken out for larger purchases, like to buy a horse, or downpayment on land, etc.... Remember, a $5 gold piece could be a miner's or logger's wage for an entire week! So to loose that, would be like
us loosing $500 today? Sure, we might have $500 in our wallet now and then, but odds are, a few $20s at the most, at any given time (well, ok, so we have ATMs and credit cards now

) But you can imagine it wasn't like what you whip out to pay for dinner, but rather, something you converted to when saving, or buying with intent? JMHO. So they are very hard to find.