My wife and I are considering purchasing a house... to give you a little bit of background, the description of it says "needs a lot of TLC", which I have confirmed to be true.

One issue with the house is the electrical service. It appears to have only 50-amp service. It's not a particularly large house (1000 sq ft). How difficult would it be to upgrade to 100 amp service?

Not very difficult at all, for an electrician that has done these before, should take about 4 - 6 hours. plus a couple of hours before for mobilization and permitting.

If someone never did a service change, it could take 2-3 days just to do the work, not including the time it takes getting all the materials, of which there are several choices, getting permit from the local inspector, consulting with the power utility for types of meters allowed, confirming serivce location, and submitting load calculations.

If someone never did a service change, it could take 2-3 days just to do the work, not including the time it takes getting all the materials, of which there are several choices, getting permit from the local inspector, consulting with the power utility for types of meters allowed, confirming serivce location, and submitting load calculations.

Thanks!

Is there a way that I could figure out if a service change has been made?

A load calculation tell you what you need in terms of a service. The Utility has to do their part. Higher service doesn't usually cost you that much more. Upgrade is co-ordinated with utility.

Underground services can be a bit pricey to upgrade.

100 A will be the minimum service put in these days. Look how your neighbor's is done to get an idea if their were upgrades.