The length of time the 1 GB card will last depends on your individual internet usage.
Donna, it is virtually impossible to give you an exact amount/time 1GB will last as every user will have different habits and there really isn't a "typical" usage.
If a person is downloading a lot of large files, streaming a lot of videos or music, uploading and downloading large numbers of photos, spending hours playing online games, etc., they could go through 1GB in one day or less.
If a person just occasionally gets on the internet during the day for an hour or so just to surf the internet, do online banking, do internet shopping, doing short stints on social media, etc. ...or those activities that do not require large amounts of bandwidth, 1GB could last for a week or more.
It will all depend on what you are doing on the internet and how long you are doing those activities. If you are a retired person that's online the majority of the day sending, uploading, or downloading photos and watching YouTube videos for hours, your usage will be very different from the person who comes home from work and spends an hour a night on the internet doing online banking and checking baseball standings ...etc.
Here is a interactive tool from Verizon Wireless that may help you determine how much data various activities will use ...choose the "3G Mobile Broadband" setting as that is what the Straight Talk Hotspot is running; Verizon's 3G mobile broadband (copy-and-paste):
Should the Straight Talk Hotspot replace your internet service provider at home? Probably not. The reason I say this is that if you do "typical" activities that most do at home and have multiple users, you will go through quite a few of these data service cards and it will become expensive.
Personal or mobile hotspots are really designed to be used by those who want their own wi-fi connection to take with them, on the go, to supply an internet connection for a laptop, tablet, smartphone, etc. so they won't have to search for a public wi-fi source such as Starbucks, hotel, airport, etc. to do internet surfing, research, light social media use, transferring small files, etc. (or for those activities associated with being mobile). So using a mobile hotspot is taking your own internet wi-fi source with you while on the go.