Solo Self-Found is IdleWorlds' hard mode league. When you create an SSF character, you're committing to a single restriction that changes everything: you cannot use the player market. Every piece of gear you wear must come from your own Smithing queue. Every potion you drink must come from your own Alchemy sessions. Every resource you use must come from your own gathering. Nothing can be purchased from other players.
That restriction sounds simple, but its implications cascade through every decision you make. In Standard mode, a player who hits a wall at Tier 8 Smithing because they've run low on ore can buy Tier 8 ore from the market and keep going. An SSF player has no such option — they have to farm the ore themselves. Every gap in your skill progression is your own problem to solve. This makes SSF substantially harder than Standard, and it also makes it substantially more rewarding when you clear those walls.
SSF characters have a separate leaderboard from Standard characters. Your ranking is compared only against other SSF players, so the competitive context is appropriate. When an SSF player achieves a rare cache drop, unlocks a high-tier zone, or reaches a skill milestone, the world chat announcement includes [SSF] to mark the achievement correctly. The community recognizes SSF accomplishments distinctly from Standard equivalents.
Strategy in SSF requires thinking about skill balance much more carefully than Standard. In Standard, you can afford to focus one skill heavily and buy the outputs of other skills on the market. In SSF, every skill needs to keep pace with your overall progression because there is no market to paper over the gaps. A Smithing level that falls behind Mining means you can't use the ore you're gathering. An Alchemy level that falls behind Herbing means your herbs rot in your inventory (metaphorically). SSF rewards generalist progression over specialist rushing.
The question of whether SSF is right for you comes down to what you find rewarding. If you want the purest test of your progression decisions — a mode where every advancement is entirely self-made — SSF is deeply satisfying. If you want access to the social economy of IdleWorlds, to see rare items from other players on the market, and to have the flexibility to fill your skill gaps with purchased materials, Standard is the better fit. The game doesn't judge either choice: SSF and Standard are both complete, supported game modes.
One practical note: SSF is selected at character creation and cannot be switched after the fact. Take the time to understand what you're committing to before choosing it. That said, many players who start in Standard eventually create a second SSF character to experience the different challenge, and players in the community are generally happy to give SSF-specific advice to newcomers choosing that path.