For me, personally: - One aggregated portfolio position over time would be enough for me i think - Once per day is fine - Given crypto volatility, 1 year wou

For me, personally: - One aggregated portfolio position over time would be enough for me i think - Once per day is fine - Given crypto volatility, 1 year would work. Maybe a combo of image caching and time series caching would make this economical. Image caching for aggregated portfolio position - and if you're generating the image everyday (or eventually more frequently) for many portfolios then you could calculate and cache the individual coin time series and use that cache to aggregate and generate many charts.